[Test] Handle exceptions from non-blocking blocks

[himani2411]

Description of changes

The rescue nil means the before block still attempts to warm up the yum cache, but if it fails, the test proceeds anyway and lets InSpec's own internal yum -v repolist all call handle it.

Our tests fails with below

2026-03-06 00:34:13.640000  Stdout: �[38;5;9m  ×  tag:install_lustre_client_installed: Verify that lustre client is installed (1 failed)�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  System Package kmod-lustre-client is expected to be installed�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  System Package lustre-client is expected to be installed�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  System Package kmod-lustre-client version is expected to cmp >= "2.12"�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  System Package lustre-client version is expected to cmp >= "2.12"�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;9m     ×  YumRepo aws-fsx is expected to exist
2026-03-06 00:34:13.640000  Stdout:      Command `yum -v repolist all` timed out after  seconds�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  YumRepo aws-fsx is expected to be enabled�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  YumRepo aws-fsx baseurl is expected to include "fsx-lustre-client-repo.s3.amazonaws.com"�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m  ✔  tag:install_lustre_lnet_kernel_module_enabled: Verify that lnet kernel module is enabled�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  Kernel Module lnet is expected to be loaded�[0m
2026-03-06 00:34:13.640000  Stdout: �[38;5;41m     ✔  Kernel Module lnet is expected not to be disabled�[0m

References

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