Add 'additionalFields' Field to extract additional data from MSGraph

[JRaver]

Description of your changes

Adds optional additionalFields []string to the Input type, allowing consumers to include extra Microsoft Graph API attributes in query results beyond the fixed default set. Supported for all four query types: UserValidation, GroupObjectIDs, ServicePrincipalDetails, and GroupMembership.

Implementation notes for reviewers:

Field values are resolved via reflection (GetCity(), GetJobTitle(), etc.) rather than GetAdditionalData(), because the kiota-generated SDK deserializes known Graph properties into typed struct fields — GetAdditionalData() only contains OData extension attributes. The helper falls back to additionalData for true extension attributes.
GroupMembership dynamically builds the nested $expand string (members($select=id,displayName,...,extraField)) to include additional fields in the Graph API request.
Unknown field names are logged at Info level and skipped — no reconcile failure.
Implement #121
Tested with the crossplane v2.3.4

Fixes #
README.md
example/user-validation-additional-fields-example.yaml
fn.go
fn_test.go
input/v1beta1/input.go
input/v1beta1/zz_generated.deepcopy.go
package/input/msgraph.fn.crossplane.io_inputs.yaml

I have:

• Read and followed Crossplane's contribution process.
• Added or updated unit tests for my change.

[JRaver]

@kaessert @jakubramut Please take a look on the PR when you will have time. Thanks)

[vtl-1]

👍