Jetpack Social: Update the jetpack social sharing

[enejb]

Updates the Apps to have make Jetpack Social more predominant in the apps.
See pdrWKz-vt-p2

To test:

Go to Site > Settings > Sharing
Notice the new label.
Add a social account. Notice it says share post to %.

Go create a new post.
Select Post settings.
Notice it says Jetpack Social as a heading for the social connections.

Regression Notes

1. Potential unintended areas of impact
   No regressions this is a text change only.

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   I looked at the UI in the.

3. What automated tests I added (or what prevented me from doing so)
   none.

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• 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.

[wpmobilebot]

You can test the changes in Jetpack from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr19262-7f5264a on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[wpmobilebot]

You can test the changes in WordPress from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr19262-7f5264a on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[hassaanelgarem]

Tested on Jetpack and WordPress.
Works as described 🚀