Blogging Prompt Compact Card: correctly display prompt text

[ScoutHarris]

Ref: #18572

The prompt text displayed on the compact card is now decoded so XML characters are displayed correctly.

In addition, a textForDisplay method is added to BloggingPrompt, and all prompt displays now use it.

To test:

• Enable bloggingPrompts feature flag.
• Verify the prompt text in the FAB header, dashboard prompt card, and prompts list is displayed correctly.
  • Today's prompt may not have XML characters, but since all three views use the new method, verifying the prompts list should suffice.

Compact Card Before	Compact Card After

Cards	List

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)
   N/A

3. What automated tests I added (or what prevented me from doing so)
   N/A

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 pr18653-c7f4dbb 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 pr18653-c7f4dbb on your iPhone

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

[wargcm]

LGTM!

[ScoutHarris]

Thanks @wargcm !