fix tsh logout flags

[GavinFrazar]

Changelog: Fixed a bug where tsh logout failed to parse flags passed with spaces.

Fixes #33681

• tsh logout flags do not work. #33681

Before

$ tsh logout --user gavin.frazar@goteleport.com --proxy=gavin-leaf.cloud.gravitational.io
ERROR: unexpected argument: gavin.frazar@goteleport.com

$ tsh logout --user=gavin.frazar@goteleport.com --proxy gavin-leaf.cloud.gravitational.io
ERROR: unexpected argument: gavin-leaf.cloud.gravitational.io

After

$ tsh logout --user gavin.frazar@goteleport.com --proxy gavin-leaf.cloud.gravitational.io:443
Logged out gavin.frazar@goteleport.com from gavin-leaf.cloud.gravitational.io.

[tigrato]

Not related but can you also fix this log message:

Specify --proxy and --user to remove keys for specific user from a proxy or neither to log out all users from all proxies.

After reading it 10 times, I can't understand what it means

[GavinFrazar]

Not related but can you also fix this log message:

Specify --proxy and --user to remove keys for specific user from a proxy or neither to log out all users from all proxies.

After reading it 10 times, I can't understand what it means

how's this?

$ ~/code/teleport/build/tsh logout --user=gavin
Specify --proxy to log out user "gavin" from a specific proxy or remove the --user flag to log out all users from all proxies.

$ ~/code/teleport/build/tsh logout --proxy=gavin-leaf.cloud.gravitational.io:443
Specify --user to log out a specific user from "gavin-leaf.cloud.gravitational.io" or remove the --proxy flag to log out all users from all proxies.

[public-teleport-github-review-bot]

@GavinFrazar See the table below for backport results.

Branch	Result
branch/v14	Create PR
branch/v15	Create PR
branch/v16	Create PR