nimbus-fml.sh is failing in iOS with a local a-s

[mhammond]

STR:

• Follow these instructions
• Run ./bootstrap.sh in the local ios checkout
• Attempt to build

The build fails with output that looks roughly like:

Using bin/nimbus-fml-configuration.sh as config
Modifying with bin/nimbus-fml-configuration.local.sh
+ shift 1
+ ((  0  ))
+ '[' -z nimbus.fml.yaml ']'
+ '[' -n '' ']'
+ '[' -z '' ']'
+ find_as_version
++ grep -A 3 https://github.com/mozilla/rust-components-swift /Users/skip/src/moz/firefox-ios/firefox-ios/Client.xcodeproj/project.pbxproj
++ grep -E -o '\d+\.\d+\.\d+'
+ number_string=

After throwing a few things at a wall to see what sticks, I got a local build by:

• changing this grep line to end with || true - I think the script stopped here because grep didn't find the string so exited with a non-zero code, which aborted the entire script.
• removing the first $ in this line but that might have been a local artifact of the shell I was using so may not be strictly necessary.

No idea why this is breaking recently, but cc @jhugman @brennie - it should be easy to repro locally.

┆Issue is synchronized with this Jira Task