use fixme type instead of `any`
use fixme type instead of `any`

Summary:
$FlowFixMe is blessed as a suppressed type. At the same time, strict mode is blind to it. This makes
it a useful alternative to `any` to mask signature verification errors in generated signatures.

Reviewed By: panagosg7

Differential Revision: D13254141

fbshipit-source-id: 80761a8c9dd44bfcfaa1d57f1a4da24c664a18ec

nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow