fix(vanta): drop the dead whenOperation from the removed-subblock entry

migrateBlockSubblockIds handles a _removed_ target before it consults
whenOperation, so the scope was never applied. Mine was the only _removed_
entry in the file carrying one.

Unconditional deletion is also what this case wants. Subblock values are
keyed by id and are not cleared when the operation changes, so a user who
filled the MIME field and then switched the block to another operation has
the value stored under that operation; a scoped delete would strand it
permanently. The field no longer exists for any operation, so it should go
regardless of the stored operation.

Author: waleedlatif1

apps/sim/lib/workflows/migrations/subblock-migrations.ts

@@ -298,13 +298,7 @@ export const SUBBLOCK_ID_MIGRATIONS: Record<string, readonly SubblockIdMigration
    * that resolution is never empty, so the field's value lost the `||` chain every
    * time. Dropped rather than renamed — there is no field for the value to move to.
    */
-  vanta: [
-    {
-      from: 'uploadMimeType',
-      to: '_removed_uploadMimeType',
-      whenOperation: ['upload_document_file'],
-    },
-  ],
+  vanta: [{ from: 'uploadMimeType', to: '_removed_uploadMimeType' }],
 }
 
 /** Reads the value out of a stored subblock entry, tolerating a bare value. */