Update libssh to 0.11.1

[Sploder12]

Sets the timeout to infinite since no messages for extended periods of time is expected behavior. Libssh updated to fix timeout being ignored.
Sets the pty mode explicitly to default since Libssh updated to inherit settings from stdin.

Fixes #3745

[codecov]

Codecov Report

Attention: Patch coverage is 32.00000% with 17 lines in your changes missing coverage. Please review.

Project coverage is 88.80%. Comparing base (bf3719d) to head (94890e4).
Report is 253 commits behind head on main.

Files with missing lines	Patch %	Lines
src/platform/platform_unix.cpp	0.00%	14 Missing ⚠️
src/sshfs_mount/sshfs_mount.cpp	75.00%	2 Missing ⚠️
src/platform/console/unix_console.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3735      +/-   ##
==========================================
- Coverage   88.93%   88.80%   -0.14%     
==========================================
  Files         254      255       +1     
  Lines       14299    14569     +270     
==========================================
+ Hits        12717    12938     +221     
- Misses       1582     1631      +49     

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[ricab]

Nice work Trevor, thanks. I ask only for some unit tests for the new code. Other than that, +1 on my secondary review.

[Sploder12]

Some reproduction steps for the issues.

Formatting:

1. Run multipass launch -n <instance-name>
2. Run multipass shell <instance-name>
3. Observe incorrectly formatted shell and no ECHO

Mounts:

1. Run multipass launch -n <instance-name>
2. Run multipass mount <source> <target>
3. Wait ~30 seconds after mount finishes mounting
4. Run multipass shell <instance-name> (GUI doesn't have shell formatting issues)
5. Attempt to navigate to the files in <target>
6. Run ls or cd
7. Observe shell hang