[image_picker]: Bump mockito-core

Bumps [mockito-core](https://github.com/mockito/mockito) from 3.10.0 to 4.8.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v3.10.0...v4.8.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

packages/image_picker/image_picker_android/android/build.gradle

@@ -38,7 +38,7 @@ android {
         implementation 'androidx.exifinterface:exifinterface:1.3.3'
 
         testImplementation 'junit:junit:4.13.2'
-        testImplementation 'org.mockito:mockito-core:3.10.0'
+        testImplementation 'org.mockito:mockito-core:4.8.0'
         testImplementation 'androidx.test:core:1.4.0'
         testImplementation "org.robolectric:robolectric:4.8.1"
     }