fix: Include root project check in preMerge task (#1006)

The preMerge task was not running the root project's :check task, which
meant spotlessCheck was not being executed on the root project's .kts
files in CI workflows. This adds the root :check task as a dependency
to ensure all verification tasks run consistently.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: runningcode

build.gradle.kts

@@ -59,6 +59,7 @@ tasks.register("integrationTest") {
 tasks.register("preMerge") {
   description = "Runs all the tests/verification tasks on both top level and included build."
 
+  dependsOn(":check")
   dependsOn(gradle.includedBuild("sentry-kotlin-compiler-plugin").task(":check"))
   dependsOn(
     gradle