Fix wrong variable being used, improve tests

services/analyticsproviders/sentry/src/main/kotlin/io/element/android/services/analyticsproviders/sentry/SentryAnalyticsProvider.kt

@@ -124,7 +124,7 @@ class SentryAnalyticsProvider(
             transaction.removeExtra(invalidExtra.key)
         }
         val invalidTags = transaction.tags?.filter { it.value.startsWith("@") }.orEmpty()
-        for (invalidTag in invalidExtras) {
+        for (invalidTag in invalidTags) {
             transaction.removeTag(invalidTag.key)
         }