fix(deps): update dependency com.android.tools.build:gradle to v9

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
com.android.tools.build:gradle (source)	8.13.2 → 9.0.0

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Configuration

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🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: build.gradle

Command failed: ./gradlew --console=plain --dependency-verification lenient -q --write-verification-metadata sha256,pgp dependencies

FAILURE: Build completed with 3 failures.

1: Task failed with an exception.
-----------
* Where:
Build file '/tmp/renovate/repos/github/nextcloud/Android-SingleSignOn/lib/build.gradle' line: 28

* What went wrong:
A problem occurred evaluating project ':lib'.
> Failed to apply plugin 'com.android.internal.library'.
   > The 'org.jetbrains.kotlin.android' plugin is no longer required for Kotlin support since AGP 9.0.
     Solution:
       - [Recommended] Migrate this project to built-in Kotlin (https://developer.android.com/r/tools/built-in-kotlin).
       - Or set the Gradle property 'android.builtInKotlin=false' and 'android.newDsl=false' to temporarily bypass this issue.

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights from a Build Scan (powered by Develocity).
> Get more help at https://help.gradle.org.
==============================================================================

2: Task failed with an exception.
-----------
* What went wrong:
A problem occurred configuring project ':lib'.
> 'kotlin-android' plugin requires one of the Android Gradle plugins.
  Please apply one of the following plugins to ':lib' project:
  - com.android.application
  	- com.android.library
  	- com.android.dynamic-feature
  	- com.android.test
  	- com.android.instantapp
  	- com.android.feature

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights from a Build Scan (powered by Develocity).
> Get more help at https://help.gradle.org.
==============================================================================

3: Task failed with an exception.
-----------
* What went wrong:
A problem occurred configuring project ':lib'.
> 'kotlin-android' plugin requires one of the Android Gradle plugins.
  Please apply one of the following plugins to ':lib' project:
  - com.android.application
  	- com.android.library
  	- com.android.dynamic-feature
  	- com.android.test
  	- com.android.instantapp
  	- com.android.feature

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights from a Build Scan (powered by Develocity).
> Get more help at https://help.gradle.org.
==============================================================================

BUILD FAILED in 4m 18s

[tobiasKaminsky]

@David-Development since there is a change to proguard, can you test this before I merge it? :)