chore: prevent "Flash via USB" for STM32H7 radios

[pfeerick]

Temporary measure until STM32H7s can be DFU flashed.

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 44.44%. Comparing base (8a9ed8f) to head (e0aee00).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/renderer/components/flashing/FlashButton.tsx	87.50%	2 Missing ⚠️
src/renderer/pages/dev/flash/PrBuildsFlasher.tsx	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #130      +/-   ##
==========================================
+ Coverage   44.39%   44.44%   +0.04%     
==========================================
  Files         108      108              
  Lines       12673    12689      +16     
  Branches      594      597       +3     
==========================================
+ Hits         5626     5639      +13     
- Misses       7039     7042       +3     
  Partials        8        8              

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[cloudflare-workers-and-pages]

Deploying buddy with    Cloudflare Pages

Latest commit:	e0aee00
Status:	✅  Deploy successful!
Preview URL:	https://e9649715.buddy-7a6.pages.dev
Branch Preview URL:	https://head.buddy-7a6.pages.dev

View logs

[github-actions]

EdgeTX Buddy has been automatically deployed to Cloudflare.
✅ Preview: https://e9649715.buddy-7a6.pages.dev
✅ Storybook: https://e9649715.buddy-7a6.pages.dev/storybook

[pfeerick]

Preview appears to be working perfectly. This PR should be reverted once Buddy plays nicely with the STM32H7 radios.