[Reader] Use `"follow"` for tag strings instead of `"subscribe"`

[RenanLukas]

Fixes #20297

---

To Test:

1. Launch Jetpack and login
2. Do a general smoke test of Reader screens

3. All tag related strings should be using "follow" instead of "subscribe"

Regression Notes

1. Potential unintended areas of impact

   • None

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

   • Manual testing

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

   --

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PR Submission Checklist:

• [x] I have completed the Regression Notes.
• [x] I have considered adding accessibility improvements for my changes.
• [x] I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

---

Testing Checklist (strike-out the not-applying and unnecessary ones):

• [ ] WordPress.com sites and self-hosted Jetpack sites.
• [ ] Portrait and landscape orientations.
• [ ] Light and dark modes.
• [ ] Fonts: Larger, smaller and bold text.
• [ ] High contrast.
• [ ] Talkback.
• [ ] Languages with large words or with letters/accents not frequently used in English.
• [ ] Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• [ ] Large and small screen sizes. (Tablet and smaller phones)
• [ ] Multi-tasking: Split screen and Pop-up view. (Android 10 or higher)

[dangermattic]

	2 Warnings
:warning:	strings.xml files should only be updated on release branches, when the translations are downloaded by our automation.
:warning:	PR is not assigned to a milestone.

Generated by :no_entry_sign: Danger

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20513-2f338af
	Commit	2f338af54b522bbc62523ff92d7110127dacbe56
	Direct Download	jetpack-prototype-build-pr20513-2f338af.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20513-2f338af
	Commit	2f338af54b522bbc62523ff92d7110127dacbe56
	Direct Download	wordpress-prototype-build-pr20513-2f338af.apk

Note: Google Login is not supported on these builds.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 40.43%. Comparing base (1f319a4) to head (2f338af).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## trunk #20513 +/- ## ======================================= Coverage 40.43% 40.43% ======================================= Files 1463 1463 Lines 67305 67305 Branches 11186 11186 ======================================= Hits 27218 27218 Misses 37611 37611 Partials 2476 2476 ```

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