Update prover-testing.yml to use ubuntu-latest-128

[AlexandreBelling]

The commit attempts solving the prover CI by using a different runner

[github-actions]

Delta Summary - Kotlin Code Coverage

Generated on:	09/12/2024 - 10:10
Description	Previous	Current	Delta
Coverage date:	09/12/2024 - 10:10	09/12/2024 - 10:10
Tag:	48_10828530247	48_10828530247
Line coverage:	27.6%	27.6%	0.0%
Covered lines:	26073	26073	0
Coverable lines:	94280	94280	0
Total lines:	133202	133202	0
Branch coverage:	10.5%	10.5%	0.0%
Covered branches:	5639	5639	0
Total branches:	53419	53419	0
Method coverage:	Feature is only available for sponsors