fix(deps): update dependency com.android.tools.build:gradle to v8.6.1

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
com.android.tools.build:gradle (source)	8.6.0 -> 8.6.1

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

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

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

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.

[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: library/build.gradle

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

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
-----------
* Where:
Build file '/tmp/renovate/repos/github/nextcloud/android-library/sample_client/build.gradle' line: 22

* What went wrong:
A problem occurred evaluating project ':sample_client'.
> Failed to apply plugin 'com.android.internal.version-check'.
   > Using different versions of the Android Gradle plugin (8.6.1, 8.6.0) in the same build is not allowed.

* 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.
> Get more help at https://help.gradle.org.
==============================================================================

2: Task failed with an exception.
-----------
* Where:
Build file '/tmp/renovate/repos/github/nextcloud/android-library/sample_client/build.gradle' line: 22

* What went wrong:
A problem occurred evaluating project ':sample_client'.
> Failed to apply plugin 'com.android.internal.version-check'.
   > Using different versions of the Android Gradle plugin (8.6.1, 8.6.0) in the same build is not allowed.

* 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.
> Get more help at https://help.gradle.org.
==============================================================================

BUILD FAILED in 2m 54s

[nextcloud-android-bot]

master-IT test failed: https://www.kaminsky.me/nc-dev/android-library-integrationTests/3330-IT-master-10-14/debug/

[github-actions]

SpotBugs

Category	Base	New
Bad practice	35	35
Correctness	34	34
Dodgy code	26	26
Internationalization	6	6
Malicious code vulnerability	49	49
Multithreaded correctness	3	3
Performance	8	8
Total	161	161