Fix broken `ISSUE_TEMPLATE` due to extra `:` (#33892)

Summary:
It seems that using `:` inside the `name` field of our Issue Template broke the parsing of them. I'm fixing it here.

## Changelog

[Internal] - Fix broken `ISSUE_TEMPLATE` due to extra `:`

Pull Request resolved: https://github.com/facebook/react-native/pull/33892

Test Plan:
Tested on:
https://github.com/cortinico/react-native/issues/new/choose

Reviewed By: f-meloni, cipolleschi

Differential Revision: D36596469

Pulled By: cortinico

fbshipit-source-id: 8009a88efc800622bad493a170b054972bb2147c