Search action - Add variables to select and relations + other fixes (#12604)

- Variables can now be handled for select/multiselect/relations
- Hide field not supported in forms (source, rating)
- Add tests for schemas

Remaning issues:
- country/currency pickers not working
- stories for components
- variable picker hidden for dates

packages/twenty-shared/src/utils/validation/isValidVariable.ts

@@ -0,0 +1,3 @@
+export const isValidVariable = (variable: string): boolean => {
+  return /^{{[^{}]+}}$/.test(variable);
+};