[DataGrid] Add missing api property to GridCallbackDetails

[sai6855]

closes: #12464

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[mui-bot]

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[romgrk]

Not sure if we should add the typing or remove the field. Also I don't love too much having optional fields, it doesn't seem very clear for an external user if they should expect an API object or not. I've tagged the rest of the team for review, let's see what they think.

[cherniavskii]

I think we should make the api required.
We used to pass it conditionally because apiRef was a Pro feature back then.
It's no longer the case – the apiRef is available in every plan.

diff --git a/packages/x-data-grid/src/hooks/core/useGridStateInitialization.ts b/packages/x-data-grid/src/hooks/core/useGridStateInitialization.ts
index 860d4d505..0ab86b644 100644
--- a/packages/x-data-grid/src/hooks/core/useGridStateInitialization.ts
+++ b/packages/x-data-grid/src/hooks/core/useGridStateInitialization.ts
@@ -92,11 +92,7 @@ export const useGridStateInitialization = <PrivateApi extends GridPrivateApiComm
         const model = controlState.stateSelector(newState, apiRef.current.instanceId);
 
         if (controlState.propOnChange && hasPropChanged) {
-          const details =
-            props.signature === GridSignature.DataGridPro
-              ? { api: apiRef.current, reason }
-              : { reason };
-          controlState.propOnChange(model, details);
+          controlState.propOnChange(model, { api: apiRef.current, reason });
         }

[romgrk]

Sidenote but I don't like that we don't have a strict convention of either always apiRef or always api. Sometimes we need to do awkward conversions like { current: api } to create a new "ref".