Social: Update media auto-conversion/validation notices in the editor

[manzoorwanijk]

Proposed changes:

• Remove auto-conversion notices from the editor
• Add a new media requirements notice

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

• Go to post editor
• Upload an invalid media
• Confirm that you see the updated notice

BEFORE	AFTER

[github-actions]

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[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the update/social/auto-conversion-notice branch.

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[spsiddarthan]

Code looks good, but I will give it a proper test on Monday. @gmjuhasz will be back as well and would be good to get his thoughts as well on this.

[gmjuhasz]

This looks close, but I had some issues while testing. We have to keep in mind that it's still possible that auto-conversion would be off for some sites.

[gmjuhasz]

Works well now