Variables: Support raw values of boolean type (#34727) (#35075)

(cherry picked from commit 4137534650)

Co-authored-by: Simon Podlipsky <simon@podlipsky.net>

public/app/features/variables/utils.test.ts

@@ -169,6 +169,7 @@ describe('ensureStringValues', () => {
     ${[1, 2]}          | ${['1', '2']}
     ${'1'}             | ${'1'}
     ${['1', '2']}      | ${['1', '2']}
+    ${true}            | ${'true'}
   `('when called with value:$value then result should be:$expected', ({ value, expected }) => {
     expect(ensureStringValues(value)).toEqual(expected);
   });

public/app/features/variables/utils.ts

@@ -239,5 +239,9 @@ export function ensureStringValues(value: any | any[]): string | string[] {
     return value;
   }
 
+  if (typeof value === 'boolean') {
+    return value.toString();
+  }
+
   return '';
 }