fix: push error handling

[CristiCanizales]

What does this PR do?

• Fixes error handling for push command

What issues does this PR fix or reference?

@W-14717018@

Functionality Before

• no output after a failed push

Functionality After

• correct output after a failed push

[peternhale]

Arrow functions! Thank you!

[daphne-sfdc]

Approved! 🎉

Commands tested:

• SFDX: Push Source to Default Org (push to empty scratch org) ✅
• SFDX: Push Source to Default Org (pushed no changed files successfully) ✅
• SFDX: Push Source to Default Org (change a file in local, no conflicts) ✅
• SFDX: Push Source to Default Org (change a file in org, no conflicts) ✅
Note: Since I did not pull the file after changing it in the org, I expected the file to be reverted to what I had in local when I ran the push because that's what happens when I run deploy. But this was the behavior in the currently published version v59.16.0 so I'm going with what's there.

• SFDX: Push Source to Default Org (failed because of a conflict) ✅

• SFDX: Push Source to Default Org (push to empty scratch org) ✅
• SFDX: Push Source to Default Org and Ignore Conflicts (pushed no changed files successfully) ✅
• SFDX: Push Source to Default Org and Ignore Conflicts (change a file in local, no conflicts) ✅
• SFDX: Push Source to Default Org and Ignore Conflicts (change a file in org, no conflicts) ✅
Note: Same as above. Not the behavior that I would expect, but accepting it because it's the original behavior.

• SFDX: Push Source to Default Org and Ignore Conflicts (overrode a conflict successfully) ✅