Allow every Delta txn other than those containing Metadata updates against blind appends

Now any transaction which has non-file actions goes through conflict detection against blind append unlike before. This may lead to failure of such transactions.

This was intentionally done to stop METADATA / other non-file-action transactions to follow conflict detection. But as a side effect, Streaming Updates (which have SetTransaction action) also started following this flow and started failing.

Instead of allowList, we want to move to blockList approach. The blockList approach is less safe from correctness perspective but more safe from rollout perspective.

Added UT

GitOrigin-RevId: d09aea4bacbe6de3d000cde58c84f1d9ee1bb638

Author: prakharjain09

core/src/main/scala/org/apache/spark/sql/delta/ConflictChecker.scala

@@ -53,8 +53,11 @@ private[delta] class CurrentTransactionInfo(
   /** Final actions to commit - including the [[CommitInfo]] */
   lazy val finalActionsToCommit: Seq[Action] = actions ++ commitInfo
 
-  /** Whether this transaction wants to commit actions other than [[FileAction]] */
-  val hasOnlyFileActions = actions.forall(_.isInstanceOf[FileAction])
+  /** Whether this transaction wants to make any [[Metadata]] update */
+  lazy val metadataChanged: Boolean = actions.exists {
+    case _: Metadata => true
+    case _ => false
+  }
 }
 
 /**
@@ -166,7 +169,7 @@ private[delta] class ConflictChecker(
     recordTime("checked-appends") {
       // Fail if new files have been added that the txn should have read.
       val addedFilesToCheckForConflicts = isolationLevel match {
-        case WriteSerializable if currentTransactionInfo.hasOnlyFileActions =>
+        case WriteSerializable if !currentTransactionInfo.metadataChanged =>
           winningCommitSummary.changedDataAddedFiles // don't conflict with blind appends
         case Serializable | WriteSerializable =>
           winningCommitSummary.changedDataAddedFiles ++ winningCommitSummary.blindAppendAddedFiles