fix: parse 19-byte PASYOU bike packets

[cagnulein]

Summary

• Allow PASYOU 19-byte packets through the AppGate USB bike parser length guard.
• Fix missing speed, cadence, resistance, and power parsing for PASYOU-0526.

Evidence

Discussion #4866 shows repeated 19-byte PASYOU packets received by
trxappgateusbbike::characteristicChanged(), followed by an immediate return
from the packet-length validation.

Test plan

• Compiled trxappgateusbbike.cpp successfully.
• Verified git diff --check.
• Full build remains blocked by the pre-existing missing
  smtpclient/src/SmtpMime dependency.

Refs #4866