SLCORE-1140: Don't log an error when not in Git repository

Currently when users are not in a Git repository there is an error logged for every action trying to invoke Git. This is too noisy and misleading as this is not an actual error.

client/java-client-utils/src/main/java/org/sonarsource/sonarlint/core/client/utils/GitUtils.java

@@ -50,7 +50,7 @@ public static Repository getRepositoryForDir(Path projectDir, ClientLogOutput cl
         .findGitDir(projectDir.toFile())
         .setMustExist(true);
       if (builder.getGitDir() == null) {
-        clientLogOutput.log("Not inside a Git work tree: " + projectDir, ClientLogOutput.Level.ERROR);
+        clientLogOutput.log("Not inside a Git work tree: " + projectDir, ClientLogOutput.Level.DEBUG);
         return null;
       }
       return builder.build();