Re-align tests with Twitter's upstream oEmbed behavior

[gfscott]

Twitter changed its oEmbed API by adding an extra newline at the end of the returned HTML string. This updates the tests so they account for the change.

Annoying but I guess this is why I made these tests in the first place, so we'd know if the API contract changed. I'm not making a changeset or bumping the version here because it's really a change on Twitter's end, not ours. And I think if you're using oEmbed, then you've opted in to accepting the HTML content returned from that third-party service.

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Latest commit: 24729e1d45d4f83d2f0aea02d8d75b3792b15317

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c95fb38) 100.00% compared to head (24729e1) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #218 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 6 6 Lines 96 96 ========================================= Hits 96 96 ```

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