[gen3] ble: fix unintialized scan_phys in default scan parameters

[avtolstoy]

Problem

scan_phys in default BLE scan parameters are not initialized.

Solution

Initialize correctly.

Steps to Test

Run wiring/ble* tests.

Example App

N/A

References

N/A

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Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)

[tstellanova]

Verified with ble scanner app:

• Flash tracker to dvos 3.1.0
• Flash with nortrack built against 3.0.0
• Verify ble beacons are not scanned correctly
• Build and flash dvos with this PR changelist
• reflash nortrack built against 3.0.0
• Verify ble beacons are scanned correctly

[avtolstoy]

Thanks folks. I'm merging this and will add a couple of PRs on top:

1. -Wextra fixes
2. Changes to BLE tests to be non-interactive and use device-os-test-runner