Use dbcmd.WithPrintFormat only for preview of teleterm gateway command

[ravicious]

Fixes #39836.

Changelog: Fixed "Invalid URI" error when starting mongosh from database connection tab in Teleport Connect

Currently lib/teleterm uses dbcmd.WithPrintFormat when generating db commands. This option is meant to be used when the command is printed rather than executed, i.e. tsh db config --format cmd. It wraps connection strings in quotes. This way when the user copies a command and tries to execute it in a shell, the shell doesn't interpret certain characters in the connection string as special characters.

This worked in Connect because for a long time we did put those commands directly into a shell. However, in #26441 we switched to spawning CLI clients directly, which means that the quotes are at best unnecessary and at worst cause problems like the one described in #39836.

To fix this, daemon.Service.GetGatewayCLICommand returns two exec.Cmds: one that doesn't use the print format and one that does. The one that does use the print format should be used for api.GatewayCLICommand.Preview, while other fields should come from the exec.Cmd that doesn't use the print format.

This way when the user clicks "Run", we execute the command without the quotes. But in the UI we display the version with the quotes, so that the user can simply copy and paste the command somewhere outside of Teleport Connect.

At the moment it mostly affects Mongodb. Looking at dbcmd, I don't think other protocols were affected.

[ravicious]

@probakowski Ping, we have a customer waiting for this fix.

[public-teleport-github-review-bot]

@ravicious See the table below for backport results.

Branch	Result
branch/v13	Failed
branch/v14	Failed
branch/v15	Create PR