### Description
Upgrade to gradle plugin 9.0. This adds support for Java 25
### Checklist
<!--
To help us keep the issue tracker clean and work as efficient as
possible,
please make sure that you have done all of the following.
You can tick the boxes below by placing an x inside the brackets like
this: [x]
-->
- [x] I have read the contribution guidelines:
https://github.com/AntennaPod/AntennaPod/blob/develop/CONTRIBUTING.md#submit-a-pull-request
- [x] I have performed a self-review of my code, going through my
changes line by line and carefully considering why this line change is
necessary
- [x] I have run the automated code checks using `./gradlew checkstyle
spotbugsPlayDebug spotbugsDebug :app:lintPlayDebug`
- [x] My code follows the style guidelines of the AntennaPod project:
https://antennapod.org/contribute/develop/app/code-style
- [x] I have mentioned the corresponding issue and the relevant keyword
(e.g., "Closes: #xy") in the description (see
https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)
- [x] If it is a core feature, I have added automated tests
+ Complete earlier update in commit 5f23a3ae4d.
I used the following command to update all files: `$ gradle wrapper`.
+ Convert line endings from CRLF to LF.
