Switch to using diff-cover for the Coverage gate (#33673)

* Switch to using diff-cover for the Coverage gate

Enabling developers to check their PR coverage without waiting for CI

* Remove sonar-project.properties - in automatic mode Sonar will not read this file

* Add note to CONTRIBUTING.md

* Skip sonar in MQ

packages/vite-common/package.json

@@ -13,7 +13,6 @@
         "typescript": "catalog:"
     },
     "peerDependencies": {
-        "@vitest/coverage-v8": "catalog:",
-        "vitest-sonar-reporter": "catalog:"
+        "@vitest/coverage-v8": "catalog:"
     }
 }

packages/vite-common/vite.config.ts

@@ -31,13 +31,6 @@ const slowTestReporter: Reporter = {
 // if we're running under GHA, enable the GHA & Sonar reporters
 if (env["GITHUB_ACTIONS"] !== undefined) {
     reporters.push(["github-actions", { silent: false }]);
-    reporters.push([
-        "vitest-sonar-reporter",
-        {
-            outputFile: "coverage/sonar-report.xml",
-            onWritePath: (path): string => `${process.cwd()}/${path}`,
-        },
-    ]);
 
     // if we're running against the develop branch, also enable the slow test reporter
     if (env["GITHUB_REF"] == "refs/heads/develop") {