Add fetcher.reset() API

[brophdawg11]

RFC: #10231

See also remix-run/remix#2749

[github-actions]

🤖 Hello there,

We just published version 7.9.2-pre.0 which involves this issue. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 7.9.2 which involves this issue. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!