Remove Giphy code

[ScoutHarris]

Ref #13803

• Shared PR: Remove Giphy tracks WordPress-iOS-Shared#264 (to remove Tracks)
• Kit PR: Update Shared pod version. WordPressKit-iOS#249 (just to update Shared pod)
• Auth PR: Update Kit and Shared pods. WordPressAuthenticator-iOS#301 (just to update Shared & Kit pods)

(Sorry about all the pod PRs. Shared is the only one with actual changes, but I had to update the other two to satisfy dependencies.)

This removes all Giphy related code. The only remnants should be localized strings, which should get removed when translations are updated.

To test:
Giphy has been disabled for quite a while, so there should be no visible changes. So just make sure other media is still functional.

• Verify the app builds and runs with no Giphy related warnings/errors.
• Verify media import via Free Photo Library.
• Verify media import via Free GIF Library.

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

	Warnings
⚠️	PR has more than 500 lines of code changing. Consider splitting into smaller PRs if possible.

Generated by 🚫 dangerJS

[peril-wordpress-mobile]

You can trigger an installable build for these changes by visiting CircleCI here.

[github-actions]

	Warnings
⚠️	PR has more than 500 lines of code changing. Consider splitting into smaller PRs if possible.

Generated by 🚫 dangerJS against 8bbd606

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[Gio2018]

Tested on iPhone 11 Max Pro Simulator - 13.5 and worked as described.
Also, no traces of giphy were found in the code (except, like you said in the comments, for the Localizable.strings that will be updated automatically)

[ScoutHarris]

Thanks @Gio2018 !