[PM-22146] Remove reference to JSON_PATH_EXISTS for old migration scripts for SH instances running older SQL Server versions (#5894)

(cherry picked from commit 9ad2d61303c4ac762cf5961dc3ef53715d6dd478)

util/Migrator/DbScripts/2025-04-16_00_AttachmentJsonValidation.sql

@@ -129,7 +129,7 @@ BEGIN
     END
 
     -- Check if the attachment exists before trying to remove it
-    IF JSON_PATH_EXISTS(@CurrentAttachments, @AttachmentIdPath) = 0
+    IF JSON_QUERY(@CurrentAttachments, @AttachmentIdPath) IS NULL
     BEGIN
         -- Attachment doesn't exist, nothing to do
         RETURN;