Revert the deletion of setupLocalGitRepo method

It has been unused earlier, but now used again in
`AbstractTransportVersionFuncTest`

Author: jozala

build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/transport/AbstractTransportVersionFuncTest.groovy

@@ -116,4 +116,12 @@ class AbstractTransportVersionFuncTest extends AbstractGradleFuncTest {
         execute("git checkout -b main")
         execute("git checkout -b test")
     }
+
+    void setupLocalGitRepo() {
+        execute("git init")
+        execute('git config user.email "[email protected]"')
+        execute('git config user.name "Build tool"')
+        execute("git add .")
+        execute('git commit -m "Initial"')
+    }
 }