Editor: Prevents the editor from hanging on Share text and Reblog actions

[antonis]

Fixes #14972 and wordpress-mobile/gutenberg-mobile#4040

Description

Moves shared text and reblog content setup on post creation to prevent editor from hanging

To test:

Share action

1. Select some text (e.g. on the browser)
2. Choose the share action on the context menu and select share
3. Select the WordPress app from this PR
4. Select a site
5. Verify that the editor opens with the correct shared content

Reblog action

1. Launch WPAndroid
2. Navigate to Reader
3. Find a post and tap the re-blog button
4. Select a site and press the check button at the top-right
5. Verify that the editor opens with the reblogged post content

Regression Notes

1. Potential unintended areas of impact
   N/A

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Relied on existing tests ReblogUseCaseTest and ReblogUtilsTest

3. What automated tests I added (or what prevented me from doing so)
   The code changes on the EditPostActivity are not easily testable

PR submission checklist:

• I have completed the Regression Notes.
• 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]

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

[peril-wordpress-mobile]

You can test the changes on this Pull Request by downloading the APKs:

• Jetpack-pr-15697-build-117694.apk

• WordPress-pr-15697-build-117694.apk

[develric]

This is working as described @antonis , thanks for taking care of it 🙇 ! Also code LGTM; feel free to merge once the release note is updated based on target 👍

[antonis]

Thank you for the prompt review @develric 🙇‍♂️

feel free to merge once the release note is updated based on target 👍

I'll update the release notes and merge 👍