[sonar scan] Scan public directories (#190350)

legrego helpfully pointed out that these files should be scanned - they
include client side code. The replaces the exclusion of `public` with
`target`, the compiled version of this source.

sonar-project.properties

@@ -38,15 +38,17 @@ sonar.exclusions=\
   **/mock_responses/**/*, \
   **/mocks/**/*, \
   **/node_modules/**/*, \
-  **/public/**/*, \
-  **/scripts/**/*, \
+  **/target/**/*, \
   **/storybook/**/*, \
   **/stubs.ts, \
   **/test/**/*, \
   **/test_data/**/*, \
   **/test_mocks.ts, \
   **/test_resources/**/*, \
   **/tests/**/*, \
-  src/dev/**/*
+  src/dev/**/*, \
+  x-pack/plugins/*/scripts/**/*, \
+  src/plugins/*/scripts/**/*, \
+  packages/*/scripts/**/*,
 
 sonar.javascript.node.maxspace=8192