Defer intersection monitoring until needed to prevent race conditions

[scottbell]

Closes #7277

Describe your changes:

• Wait to start observing for intersections (i.e., visibility) until renderWhenVisible is called once. This prevents every View needing to subscribe to intersection events, and prevents a race condition where the view isn't quite built yet.
• Wait to start observing canvas for visibility until we've called draw once. Prevents similar race condition as above.
• Update API documentation.

All Submissions:

• 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?
• Has associated issue been labelled unverified? (only applicable if this PR closes the issue)
• Has associated issue been labelled bug? (only applicable if this PR is for a bug fix)

[deploysentinel]

Current Playwright Test Results Summary

✅ 15 Passing

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

(Last updated on 12/15/2023 08:34:24am UTC)

Run Details

Running Workflow e2e-couchdb on Github Actions

Commit: 4dbb574

Started: 12/15/2023 08:32:41am UTC

View Detailed Build Results

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Current Playwright Test Results Summary

✅ 165 Passing - ⚠️ 1 Flaky

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

(Last updated on 12/15/2023 08:34:24am UTC)

Run Details

Running Job e2e-stable on CircleCI

Commit: 4dbb574

Started: 12/15/2023 08:17:56am UTC

⚠️ Flakes

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

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 / 54 runs failed over last 7 days	42.59% (23) 23 / 54 runs flaked over last 7 days

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View Detailed Build Results

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[codecov]

Codecov Report

Merging #7278 (4dbb574) into master (4075a31) will decrease coverage by 0.05%.
The diff coverage is 80.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7278      +/-   ##
==========================================
- Coverage   55.96%   55.91%   -0.05%     
==========================================
  Files         655      655              
  Lines       26316    26324       +8     
  Branches     2543     2544       +1     
==========================================
- Hits        14728    14720       -8     
- Misses      10881    10891      +10     
- Partials      707      713       +6     

Flag	Coverage Δ		*Carryforward flag
e2e-full	41.79% <ø> (-0.01%)	⬇️	Carriedforward from 4075a31
e2e-stable	58.40% <100.00%> (-0.01%)	⬇️
unit	49.18% <20.00%> (-0.08%)	⬇️

*This pull request uses carry forward flags. Click here to find out more.

Files	Coverage Δ
src/utils/visibility/VisibilityObserver.js	96.55% <100.00%> (+0.71%)	⬆️
src/plugins/plot/chart/MctChart.vue	43.88% <33.33%> (+0.15%)	⬆️

... and 7 files with indirect coverage changes

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[scottbell]

Before:

Before.mov

After:

After.mov

[ozyx]

LGTM

[scottbell]

@akhenry please let me know if there's anything else we need to test here

[scottbell]

@akhenry please let me know if there's anything else we need to test here

Merging for the interim, but can revert if we need.