Convert mod_messages to service provider

[joomlaweby]

Summary of Changes

Converts the messages administrator module to service provider.

This is my first pull request to Joomla! project :-).

Testing Instructions

1. Make sure you have administrator component com_messages (Private Messages) and module mod_messages enabled
2. Make sure you have at least 1 unread message
3. You should see module output

Actual result BEFORE applying this Pull Request

Module works as expected

Expected result AFTER applying this Pull Request

Module works same way as before applying pull request

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[ghost]

I have tested this item ✅ successfully on 24ba818

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/42735.}

[richard67]

@joomlaweby No need to update your branch when there are no conflicts shown. Updating the branch in validates the test counter for human test. I've restored the result from @fgsw now so it's counted again.

[joomlaweby]

@joomlaweby No need to update your branch when there are no conflicts shown. Updating the branch in validates the test counter for human test. I've restored the result from @fgsw now so it's counted again.

@richard67 OK, got it. :-)

[viocassel]

I have tested this item ✅ successfully on 769c4ab

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/42735.}

[richard67]

RTC

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/42735.}

[exlemor]

Tested successfully during PBF 2024.

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/42735.}

[LadySolveig]

Thank you @joomlaweby and also for testing and support @fgsw @viocassel @exlemor @richard67 @sandewt