fix(workflow): prevent empty variable name validation error

The validation was triggering incorrectly for empty input values. Added a check to only validate non-empty values to avoid false negatives.

web/app/components/workflow/panel/chat-variable-panel/components/variable-modal.tsx

@@ -145,7 +145,7 @@ const ChatVariableModal = ({
 
   const handleVarNameChange = (e: React.ChangeEvent<HTMLInputElement>) => {
     replaceSpaceWithUnderscreInVarNameInput(e.target)
-    if (!checkVariableName(e.target.value))
+    if (!!e.target.value && !checkVariableName(e.target.value))
       return
     setName(e.target.value || '')
   }

web/app/components/workflow/panel/env-panel/variable-modal.tsx

@@ -44,7 +44,7 @@ const VariableModal = ({
 
   const handleVarNameChange = (e: React.ChangeEvent<HTMLInputElement>) => {
     replaceSpaceWithUnderscreInVarNameInput(e.target)
-    if (!checkVariableName(e.target.value))
+    if (!!e.target.value && !checkVariableName(e.target.value))
       return
     setName(e.target.value || '')
   }