Sharing: Open Graph tags not added when using sharing buttons block instead of legacy sharing module

### Impacted plugin

Social

### Quick summary

Not sure if this is a bug or expected behaviour and just some text needs to be updated.

I am working on a FSE theme and want to add the share button blocks to my templates, which all works well :)

I enabled the JP sharing toggle in `wp-admin/admin.php?page=jetpack#/sharing` and the following message appears:

```
You are using a block-based theme. We recommend that you disable the legacy sharing feature above and add a sharing button block to your themes’s template instead
```
So I disabled the sharing toggle and just added the share buttons to my theme template, however I noticed that with the sharing toggle switched off, no og: tags appear in the html on any post or page.

If I switch the share toggle back on the og: tags appear as expected. I'm not sure if it is expected behaviour that when the share toggle is off, the og: tags should not appear in which case perhaps revise the error message as it is a bit confusing as is.

If og: tags should appear on FSE themes when the share toggle in off, they need to be added to the header...


### Steps to reproduce

1. Install a FSE theme & jetpack
2. Add share icons to the FSE theme templates or posts / pages
3. notice there are no og: meta tags in the html of any post or page
4. Enable the legacy sharing feature in `wp-admin/admin.php?page=jetpack#/sharing`
5. Notice the error message saying you should switch off legacy sharing on FSE themes
6. Go to any post or page and notice the og: meta tags are present in the html

### A clear and concise description of what you expected to happen.

og: meta tags should appear on FSE themes OR clearer instructions on how to get this to work on FSE themes

### What actually happened

_No response_

### Impact

All

### Available workarounds?

Yes, easy to implement

### If the above answer is "Yes...", outline the workaround.

- Activate this plugin: https://wordpress.org/plugins/always-use-jetpack-open-graph/ , or
- Enable the legacy share button

### Platform (Simple and/or Atomic)

_No response_

### Logs or notes

Using JP 13.8-beta

Reproduce the behavior using a block-based theme, share button blocks, and the sharing setting at wp-admin/admin.php?page=jetpack#/sharing. Trace how the sharing setting affects Open Graph tags in the page header, then confirm whether block-based sharing should provide those tags or whether the displayed guidance needs clarification; done means consistent tags or accurate instructions for the supported setup.

Written by the indexing model from the issue text.