device-xiaomi-{davinci,surya}: Move from testing to community

The SM7150 devices have seen a lot of work put into them and are generally very usable except for microphone/earpiece audio and cameras. Both of these features are still work in progress and should be available sometime in the future. They fulfil the requirements for community in the Wiki, so let's promote them.

Copy-paste of the checklist from the Wiki:

• Installation instructions must be well documented on device wiki page - ✅ xiaomi-davinci, xiaomi-surya
• Must run a (close to) mainline kernel - ✅ 6.13.2, sources from https://github.com/sm7150-mainline/linux
• Kernel must pass pmbootstrap kconfig check --community, which includes working firewall (#1119 (closed)) - ✅ The kconfig check option was added in the last kernel upgrade
• All of them must have automatic kernel upgrade working - ✅
• maintainer(s) must take part in the workflow for new postmarketOS releases:
  • Join the testing chat to coordinate the release - ✅ @Adrian @ArianK16a @jiaxyga @ungeskriptet
  • Testing their device and related fixing issues, according to the timeline (test yourself/coordinate with the Testing Team; testing one device per SoC is enough for community devices, but of course more is better) - ✅ We promise to do that and have plenty of devices spread across us 4 to test reliably
  • 2021-11 and later: track record of upgrading the kernel, device kernel or SoC kernel must at least have been upgraded through 3 kernel releases - ✅ The SM7150 kernel was added in December 2022 and has been upgraded 4 times since (less frequently recently due to UFS issues which are now resolved, but our GitHub repository was always very up to date and we'll upstream more frequently to pmaports now that issues are resolved)