Content Translation: Make blocks inside Post Content translatable when "Show template" is enabled #1115

Description

Similar to #1054, and #1052.

With "Show template" enabled, Content Translation targets the template's outer blocks instead of the blocks inside Post Content. The post's own content doesn't get translated.

Expected behavior:
Content Translation should translate the blocks inside Post Content whether "Show template" is on or off.

Step-by-step reproduction instructions

1. Enable the Content Translation experiment.
2. Open a post that has content in the editor.
3. Turn on "Show template" in the editor.
4. Start translating the post.
5. Notice that the blocks inside Post Content aren't translated.

Screenshots, screen recording, code snippet

Environment info

• WordPress Version: Latest Trunk
• AI Plugin Version: Latest Develop

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except the AI plugin.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure