Resolve #3590948 "Add TMGMT translation integration for content entities"

1. AI resuscitated/lift @tedbow's prior work from !882 (merged) (mostly: https://git.drupalcode.org/project/canvas/-/merge_requests/882/diffs?commit_id=3d08e0ef3cbce077ec542c573b461d07270bb552#8cd19b0519ffc218e1abb99edb8575b9b7a3715e).
2. Then I instructed it to maximally reuse the final test coverage that !882 landed, which tests way more edge cases. See ConfigWithComponentTreeTranslationTestBase in HEAD.
3. @wimleers thinks this should NOT be tested against both Page and Node. That was a concern in \Drupal\Tests\canvas\Kernel\Translation\ComponentTreeFieldSymmetricalTranslationSynchronizerTest::test() for Canvas' custom synchronizer, but it's not a concern here.
4. Tightened/expanded tests, incorporated @larowlan's pivot, and then addressed a huge pile of upstream bugs in both core+TMGMT to get it all to pass — summarized in https://git.drupalcode.org/project/canvas/-/merge_requests/1232#note_1257576

AI-Generated: Yes

Testing instructions

• Create a Canvas Page content entity with a non-empty component tree
• Try translating it using TMGMT
• Verify the content translation loads as expected (although ignore any problems with references, thats' for !876 to fix)

Closes #3590948 (closed)