fix type

Author: jankuca

src/notebooks/deepnote/converters/inputConverters.ts

@@ -188,7 +188,7 @@ export class InputSliderBlockConverter extends BaseInputBlockConverter<typeof De
         const value = Number.isFinite(parsed) ? parsed : fallback;
 
         this.updateBlockMetadata(block, {
-            deepnote_variable_value: value
+            deepnote_variable_value: String(value)
         });
     }
 }