Simplify media insertion flow

[jd-alexander]

Fixes #946
Gutenberg PR WordPress/gutenberg#29546

This change simplifies the media insertion flow by showing the media options sheet when you tap the Media block to add the Media placeholder to the canvas. Before you would have to add the placeholder and click for eg. Add Image for it to be shown.
To test:
WordPress/gutenberg#29546
PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered if this change warrants user-facing release notes more info and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

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[guarani]

Just adding my approval here, since I already reviewed and approved WordPress/gutenberg#25031 (review).

[guarani]

Just approving this since the linked Gutenberg PRs are approved. I think this is missing an entry in the release notes though (and we're missing an entry in the react-native-editor package change log).

[jd-alexander]

Just approving this since the linked Gutenberg PRs are approved. I think this is missing an entry in the release notes though (and we're missing an entry in the react-native-editor package change log).

Thanks. I was planning to put the release notes in and request a review from you. Can I just put them in and merge afterwards ?

[guarani]

Just approving this since the linked Gutenberg PRs are approved. I think this is missing an entry in the release notes though (and we're missing an entry in the react-native-editor package change log).

Thanks. I was planning to put the release notes in and request a review from you. Can I just put them in and merge afterwards ?

Yeah sure, I don't mind either way.

[jd-alexander]

Just approving this since the linked Gutenberg PRs are approved. I think this is missing an entry in the release notes though (and we're missing an entry in the react-native-editor package change log).

Thanks. I was planning to put the release notes in and request a review from you. Can I just put them in and merge afterwards ?

Yeah sure, I don't mind either way.

No problem. I will sync with trunk and get all these PRs merged in on Monday.