Disable refresh after for static secrets

**Is your feature request related to a problem? Please describe.**
We are implementing VSO in our blue-green applications, the refreshAfter field in vaultstaticsecret will cause issues when modifying application related secrets.

**Describe the solution you'd like**
The refreshAfter field has a default value when omitted from the vaultstaticsecret manifest. Please outline if it is possible to disable the refresh function.

**Describe alternatives you've considered**
Setting a high value would still cause the issue. We are considering versioning our vault spaces but would like to explore if disabling this feature is a possibility.

No files or tests are named. Start by tracing how refreshAfter is handled for the VaultStaticSecret manifest and read the related operator documentation. Done means there is a supported way to disable refresh without relying on an arbitrarily high value, with the behavior documented and covered by tests.

Written by the indexing model from the issue text.