feat(table): expand cell harness api

[JoepKockelkorn]

Besides text, table cells can contain other components.
Extending from ContentContainerComponentHarness
exposes more apis to query for children in the table cell.

Closes #21157

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[JoepKockelkorn]

@googlebot I signed it!

[crisbeto]

The changes are fine, but for some reason the CI didn't run on your PR. If it did, I'm pretty sure that it would've failed, because the API goldens need to be updated too. You can update them using yarn approve-api table/testing.

@josephperrott do you know why the CI didn't run here?

[crisbeto]

The same changes need to be made in the cell-harness under experimental.

[JoepKockelkorn]

The changes are fine, but for some reason the CI didn't run on your PR. If it did, I'm pretty sure that it would've failed, because the API goldens need to be updated too. You can update them using yarn approve-api table/testing.

@josephperrott do you know why the CI didn't run here?

@crisbeto Thanks for your feedback. I resolved the comments with a new commit.

[crisbeto]

It doesn't look like the CI checks ran this time around either.

[JoepKockelkorn]

@crisbeto Is there anything I can do about that?

[crisbeto]

I've heard that this can happen if somehow Circle CI is enabled on your fork so that might be something worth checking.

[josephperrott]

I looked into it and am unsure of why CircleCI did not run as expected in this case. I have manually triggered our CI run.

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