`az storage container generate-sas`: `--permissions`'s help contains duplicated entries

## Describe the bug

```
$ az storage container generate-sas -h
...
--permissions : The permissions the SAS grants. Allowed values: (a)dd (c)reate (d)elete
(l)ist (r)ead (w)rite (a)dd (c)reate (d)elete (l)ist (r)ead (w)rite. Do
not use if a stored access policy is referenced with --id that specifies
this value. Can be combined.
```

Note that `(a)dd (c)reate (d)elete (l)ist (r)ead (w)rite` are duplicated.

## Environment Summary
```
Linux-5.10.60.1-microsoft-standard-WSL2-x86_64-with-glibc2.29, Ubuntu 20.04.4 LTS
Python 3.8.12
Installer: DEB

azure-cli 2.34.1

Extensions:
confcom 0.1.0
resource-graph 2.1.0

Dependencies:
msal 1.16.0
azure-mgmt-resource 20.0.0
```