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/module-api/package.json

@@ -27,7 +27,9 @@
     "scripts": {
         "prepack": "nx build",
         "lint:types": "nx lint:types",
-        "test:unit": "vitest"
+        "test:unit": "vitest",
+        "coverage": "pnpm test:unit --coverage",
+        "coverage:diff": "diff-cover --config-file ../../diff-cover.toml coverage/lcov.info"
     },
     "devDependencies": {
         "@element-hq/vite-common": "workspace:*",
@@ -44,8 +46,7 @@
         "typescript": "^6.0.0",
         "unplugin-dts": "1.0.1",
         "vite": "catalog:",
-        "vitest": "catalog:",
-        "vitest-sonar-reporter": "catalog:"
+        "vitest": "catalog:"
     },
     "peerDependencies": {
         "@matrix-org/react-sdk-module-api": "*",