Refine WifiAccessPointSetFrequencyBands into top-level and implementation functions

[abeltrano]

Type

• Bug fix
• Feature addition
• Feature update
• Documentation
• Build Infrastructure

Side Effects

• Breaking change
• Non-functional change

Goals

• Allow the frequency bands type of an access point to be set from any API, not just WifiAccessPointSetFrequencyBands . This is primarily to allow setting the frequency bands consistently, including from other APIs like WifiAcccessPointEnable.

Technical Details

• Move most functionality from WifiAccessPointSetFrequencyBands to WifiAccessPointSetFrequencyBandsImpl.
• Add ToDot11FrequencyBands adapter for safely converting from loosely-typed frequencybands() member of WifiAccessPointSetFrequencyBandsRequest to strongly-typed version to workaround protobuf deficiency for repeated enum fields.
• Update const correctness of helper function.
• Add skeleton for WifiAccessPointEnable.
• Add extra tests for WifiAccessPointEnable matching the existing skeleton code.
• Remove extra validation function.

Test Results

• All unit tests pass.

Reviewer Focus

• None

Future Work

• Make use of WifiAccessPointSetFrequencyBands in WifiAccessPointEnable.

Checklist

• Build target all compiles cleanly.
• clang-format and clang-tidy deltas produced no new output.
• Newly added functions include doxygen-style comment block.