SafetyNet is deprecated and non-functional, any references to it should be replaced with Play Integrity API

**Describe the bug**
SafetyNet is deprecated a while ago, and is replaced with Play Integrity API. Attempting to make requests to it results in long base64 error code for 404 page.

**To Reproduce**
Steps to reproduce the behavior:
1. Open microG Settings
1. Go to 'Device Attestation'
2. Click on 'Test SafetyNet attestation'
4. See error

**Expected behavior**
Instead of 'Test SafetyNet attestation', there should be 'Test Play Integrity attestation' that should return related values. Any other occurrences of 'SafetyNet' name should also be replaced.

**System**
Android Version: 16
Custom ROM: Infinity-X 3.12

Start in microG Settings at Device Attestation and trace the action behind “Test SafetyNet attestation,” then search the project for other SafetyNet references. Replace the obsolete references with Play Integrity API terminology and behavior, and verify that the test action returns the related attestation values.

Written by the indexing model from the issue text.