Truncate snapshot name to max characters length

[falfaroc]

Description

During csi-sanity testing, there was no verification that the adjusted name of the snapshot name would be 31 characters or greater. This caused a truncated name of less than 31 characters to cause an out-of-bound exception during testing.

GitHub Issues

List the GitHub issues impacted by this PR:

GitHub Issue #
dell/csm#350

Checklist:

• I have performed a self-review of my own code to ensure there are no formatting, vetting, linting, or security issues
• I have verified that new and existing unit tests pass locally with my changes
• I have not allowed coverage numbers to degenerate
• I have maintained at least 90% code coverage
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Backward compatibility is not broken

How Has This Been Tested?

Tested locally with the csi-sanity tests. No crashing of snapshot name creations occurred.