fix: allow members with git providers permission to create and delete their own

The canAccessToGitProviders legacy override only granted read access, so
members with the Git Providers toggle enabled could not add providers — the
create/delete endpoints require gitProviders.create / gitProviders.delete.
This mirrors how the SSH Keys toggle already grants read/create/delete.

The git-provider remove endpoint now restricts non owner/admin roles to
deleting only their own providers (matching the ownership model used for
visibility and sharing), while owner/admin can still delete any provider in
the organization.

Closes #4695

packages/server/src/services/permission.ts

@@ -170,6 +170,8 @@ const getLegacyOverrides = (
 		},
 		gitProviders: {
 			read: !!memberRecord.canAccessToGitProviders,
+			create: !!memberRecord.canAccessToGitProviders,
+			delete: !!memberRecord.canAccessToGitProviders,
 		},
 	};
 };