remove --recursive flag from git submodule call in forge update

[ckoopmann]

Motivation

Currently forge update recursively updates nested dependencies which can lead to problems outlined in #2264

Solution

Remove --recursive flag from git submodule call inside forge update subcommand.

[ckoopmann]

Note that the integration tests i added depends on a repository that I created using my personal github account for reproducing this issue.
Lmk if this is an issue and I can remove the test or see if there is a way to reproduce the issue using existing repos.

[mattsse]

I guess that's reasonable, user can execute recursive updates manually

wdyt @onbjerg ?

[gakonst]

Note that the integration tests i added depends on a repository that I created using my personal github account for reproducing this issue.

Thanks! Very helpful. Upstreamed this here