Dynamic type podcasts

[bjtitus]

THIS IS AN INITIAL CONCEPT

Begins #1316

Adds UITest target + initial tests to perform accessibility audits on major tabs.

To test

Manual

• Go to the Podcasts tab
• Open the accessibility inspector
• Verify that changing the preferred text size changes text appropriately

UI Test

• Run the UI tests
• Check for errors from the accessibility audit

Checklist

• I have considered if this change warrants user-facing release notes and have added them to CHANGELOG.md if necessary.
• I have considered adding unit tests for my changes.
• I have updated (or requested that someone edit) the spreadsheet to reflect any new or changed analytics.

[pocketcasts]

	4 Warnings
⚠️	View files have been modified, but no screenshot is included in the pull request. Consider adding some for clarity.
⚠️	This PR is larger than 500 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.
⚠️	PR is not assigned to a milestone.
⚠️	No reviewers have been set for this PR yet. Please request a review from @ Automattic/pocket-casts-ios.

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