Remove Linode APIv3 support #3694

Job	Run time
Run Security Checks (3.10)	1m 4s
Generate Code Coverage (3.10)	5m 8s
Build and Test Release Artifact (3.10)	2m 28s
Micro Benchmarks (3.10)	2m 27s
Run Various Lint and Other Checks (3.10)	4m 46s
Unit Tests (Python 3.14)	2m 41s
Unit Tests (Python 3.12)	2m 14s
Build and upload Documentation (3.10)	2m 29s
Unit Tests (Python 3.13)	2m 3s
Unit Tests (Python 3.11)	1m 54s
Unit Tests (Python 3.10)	2m 18s
Unit Tests (Python pypy-3.10)	2m 36s
Build and Verify Docker Image (3.10)	2m 48s
	34m 56s

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