build(deps): bump org.slf4j:slf4j-nop in /msgraph-mail/java

Bumps org.slf4j:slf4j-nop from 2.0.14 to 2.0.15.

---
updated-dependencies:
- dependency-name: org.slf4j:slf4j-nop
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

msgraph-mail/java/app/build.gradle

@@ -14,7 +14,7 @@ archivesBaseName = 'app'
 
 dependencies {
     implementation project(':utilities')
-    implementation 'org.slf4j:slf4j-nop:2.0.14'
+    implementation 'org.slf4j:slf4j-nop:2.0.15'
     implementation 'com.google.guava:guava:33.2.1-jre'
 }