do _not_ preload the developer_key by default for User#access_tokens
do _not_ preload the developer_key by default for User#access_tokens

it prevents using the cache for it

Change-Id: If038bef3555aad71979fc9828cee29912c978c8a
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/248373
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
QA-Review: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
Product-Review: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms