fix: 2d canvas fallback logic

[ozyx]

Closes #7294

Describe your changes:

This is a subset of @scottbell 's changes in #7202
It's basically just a null check to prevent the 2D fallback code from failing.

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• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Is this change backwards compatible? For example, developers won't need to change how they are calling the API or how they've extended core plugins such as Tables or Plots.

Author Checklist

• Changes address original issue?
• Tests included and/or updated with changes?
• Command line build passes?
• Has this been smoke tested?
• Testing instructions included in associated issue OR is this a dependency/testcase change?

Reviewer Checklist

• Changes appear to address issue?
• Reviewer has tested changes by following the provided instructions?
• Changes appear not to be breaking changes?
• Appropriate automated tests included?
• Code style and in-line documentation are appropriate?
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[deploysentinel]

Current Playwright Test Results Summary

✅ 161 Passing - ⚠️ 5 Flaky

Run may still be in progress, this comment will be updated as current testing workflow or job completes...

(Last updated on 12/12/2023 11:05:10pm UTC)

Run Details

Running Job e2e-stable on CircleCI

Commit: 1e4ed36

Started: 12/12/2023 10:57:35pm UTC

⚠️ Flakes

📄   functional/plugins/plot/logPlot.e2e.spec.js • 1 Flake

Test Case Results

Test Case	Last 7 days Failures	Last 7 days Flakes
Log plot tests Log Plot ticks are functionally correct in regular and log mode and after refresh Retry 1 • Initial Attempt	0% (0) 0 / 39 runs failed over last 7 days	28.21% (11) 11 / 39 runs flaked over last 7 days

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📄   functional/plugins/notebook/restrictedNotebook.e2e.spec.js • 2 Flakes

Top 1 Common Error Messages

null	2 Test Cases Affected

Test Case Results

Test Case	Last 7 days Failures	Last 7 days Flakes
Restricted Notebook with a page locked and with an embed @addinit Allows embeds to be deleted if page unlocked @addinit Retry 1 • Initial Attempt	0% (0) 0 / 39 runs failed over last 7 days	53.85% (21) 21 / 39 runs flaked over last 7 days
Restricted Notebook with a page locked and with an embed @addinit Disallows embeds to be deleted if page locked @addinit Retry 1 • Initial Attempt	0% (0) 0 / 39 runs failed over last 7 days	41.03% (16) 16 / 39 runs flaked over last 7 days

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📄   functional/planning/timelist.e2e.spec.js • 1 Flake

Test Case Results

Test Case	Last 7 days Failures	Last 7 days Flakes
Time List Create a Time List, add a single Plan to it and verify all the activities are displayed with no milliseconds Retry 1 • Initial Attempt	11.29% (7) 7 / 62 runs failed over last 7 days	64.52% (40) 40 / 62 runs flaked over last 7 days

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📄   functional/plugins/notebook/notebookSnapshots.e2e.spec.js • 1 Flake

Test Case Results

Test Case	Last 7 days Failures	Last 7 days Flakes
Snapshot image tests Can drop an image onto a notebook and create a new entry Retry 1 • Initial Attempt	0% (0) 0 / 39 runs failed over last 7 days	56.41% (22) 22 / 39 runs flaked over last 7 days

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View Detailed Build Results

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Current Playwright Test Results Summary

✅ 14 Passing

Run may still be in progress, this comment will be updated as current testing workflow or job completes...

(Last updated on 12/12/2023 11:05:10pm UTC)

Run Details

Running Workflow e2e-couchdb on Github Actions

Commit: 1e4ed36

Started: 12/12/2023 10:57:25pm UTC

View Detailed Build Results

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[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release/3.2.0@86d4244). Click here to learn what that means.
The diff coverage is n/a.

Additional details and impacted files

@@               Coverage Diff                @@
##             release/3.2.0    #7295   +/-   ##
================================================
  Coverage                 ?   55.94%           
================================================
  Files                    ?      655           
  Lines                    ?    26249           
  Branches                 ?     2527           
================================================
  Hits                     ?    14684           
  Misses                   ?    10856           
  Partials                 ?      709           

Flag	Coverage Δ
e2e-full	41.84% <0.00%> (?)
e2e-stable	58.25% <0.00%> (?)
unit	49.23% <0.00%> (?)

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