Correct the Flipper BLE advertisement data length

[p-keminer]

Stack

• Draft follow-up to Fix Samsung BLE model selection bounds #1426.
• Until Fix Samsung BLE model selection bounds #1426 merges, this comparison includes the Samsung bounds commit; the intended review delta is the final one-line Flipper length correction.

Summary

• change the Flipper Manufacturer Specific Data AD length from 0x05 to 0x09

Protocol basis

The Bluetooth GAP format defines the length octet as the number of following data octets, with the first data octet being the AD type. This structure contains one type byte (0xFF), two company-ID bytes, and six manufacturer payload bytes: 1 + 2 + 6 = 9. See the Bluetooth Core Generic Access Profile.

Testing boundary

• The corrected source was build-covered in the cumulative validation firmware.
• The post-fix Android btsnoop contained no Flipper signature, likely due to filtering, so the corrected Flipper frame was not independently observed over the air.
• This PR is intentionally a draft and does not claim a complete post-fix OTA pass.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.40%. Comparing base (66f3c81) to head (40c8441).
⚠️ Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
esp32_marauder/WiFiScan.cpp	0.00%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #1447   +/-   ##
=======================================
  Coverage     0.40%   0.40%           
=======================================
  Files           20      20           
  Lines        17176   17176           
  Branches        11      11           
=======================================
  Hits            69      69           
  Misses       17103   17103           
  Partials         4       4           

Flag	Coverage Δ
firmware-unit-tests	0.40% <0.00%> (ø)

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[p-keminer]

All 22 firmware matrix builds and the Native Unity tests pass on this head. The remaining red statuses are limited to the repository-wide Codecov policy addressed separately in #1448.