Update verifyCodeStyle and applyCodeStyle to be what we really require (#30777)

Previously it included a coarse grained Java reformat which it seems was never
quite worked through (reformatting generated sources etc), so go back on that,
and make sure verifyCodeStyle is exactly what we require for PR validation to pass
(and that it does not diverge)

.github/workflows/build-test-prValidation.yml

@@ -32,7 +32,7 @@ jobs:
           sbt -jvm-opts .jvmopts-ci \
           -Dsbt.override.build.repos=false \
           -Dsbt.log.noformat=false \
-          scalafmtCheckAll scalafmtSbtCheck headerCheckAll
+          verifyCodeStyle
 
   pull-request-validation:
     name: Check / Tests