Downgrade Gradle wrapper to version 8.7 to resolve compatibility issues

Author: rabestro

exercises/practice/minesweeper/gradle/wrapper/gradle-wrapper.jar

@@ -1,7 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.2.1-bin.zip
-networkTimeout=10000
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists