Persistent burst buffers cannot use underscores in their names

[jsteel44]

If you name a persistent burst buffer with an underscore it causes creation to fail, but not only that, running an squeue for example prints out a huge error, the top of which I've pasted here but this is only a snippet:

(burst_buffer/datawarp: _create_persistent: panic: invalid session name: 'test_1' [recovered]
        panic: invalid session name: 'test_1'

goroutine 1 [running]:
main.main.func1()
        /home/circleci/data-acc/cmd/dacctl/main.go:187 +0xb9
panic(0xaccca0, 0xc0002c4060)
        /usr/local/go/src/runtime/panic.go:522 +0x1b5
log.Panicf(0xbf1b17, 0x1a, 0xc0001546c0, 0x1, 0x1)
        /usr/local/go/src/log/log.go:340 +0xc0
github.com/RSE-Cambridge/data-acc/internal/pkg/registry_impl.getSessionKey(0x7ffccbdd0e74, 0x7, 0x42c64f, 0x8)
[snip]

Not allowing underscores is fine (unless this is an easy fix) however maybe the DAC should handle this issue a little better?