Rename M3Theme to AppThemeM3

[nbradbury]

This PR renames M3Theme to AppThemeM3 to make it more consistent with the existing AppTheme. There's really nothing to test - it's just a simple rename.

Note: This is a draft because #21315 should be merged first.

[dangermattic]

	2 Warnings
:warning:	View files have been modified, but no screenshot or video is included in the pull request. Consider adding some for clarity.
:warning:	PR is not assigned to a milestone.

Generated by :no_entry_sign: Danger

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr21316-0ed4e45
	Commit	0ed4e458040b99a07a127f65be3ae0e3d64eec9f
	Direct Download	jetpack-prototype-build-pr21316-0ed4e45.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr21316-0ed4e45
	Commit	0ed4e458040b99a07a127f65be3ae0e3d64eec9f
	Direct Download	wordpress-prototype-build-pr21316-0ed4e45.apk

Note: Google Login is not supported on these builds.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 17 lines in your changes missing coverage. Please review.

Project coverage is 40.23%. Comparing base (db421cb) to head (0ed4e45). Report is 3 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...s/android/ui/domains/management/MyDomainsScreen.kt	0.00%	3 Missing :warning:
...ns/management/composable/DomainsSearchTextField.kt	0.00%	2 Missing :warning:
.../ui/domains/management/composable/PrimaryButton.kt	0.00%	2 Missing :warning:
.../purchasedomain/composable/PurchaseDomainScreen.kt	0.00%	2 Missing :warning:
...ui/prefs/accountsettings/components/FlatButtons.kt	0.00%	2 Missing :warning:
...s/android/ui/domains/management/DomainStatusRow.kt	0.00%	1 Missing :warning:
...s/android/ui/domains/management/DomainsListCard.kt	0.00%	1 Missing :warning:
...android/ui/main/feedbackform/FeedbackFormScreen.kt	0.00%	1 Missing :warning:
...accountsettings/components/AccountClosureDialog.kt	0.00%	1 Missing :warning:
...s/accountsettings/components/CloseAccountButton.kt	0.00%	1 Missing :warning:
... and 1 more

Additional details and impacted files

@@           Coverage Diff           @@
##            trunk   #21316   +/-   ##
=======================================
  Coverage   40.23%   40.23%           
=======================================
  Files        1536     1536           
  Lines       70252    70252           
  Branches    11543    11543           
=======================================
  Hits        28263    28263           
  Misses      39542    39542           
  Partials     2447     2447           

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[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[nbradbury]

Alternatively, we could rename both to include a incrementing number—AppThemeM2 and AppThemeM3

I like this idea! If it's okay with you, I'd prefer to make that change in a separate PR.

[dcalhoun]

If it's okay with you, I'd prefer to make that change in a separate PR.

Of course! 🚀