fix(shell-api): Fix invalid regular expression error in db.currentOp() MONGOSH-1703

[gagik]

Fixes a bug where a regular expression error in db.currentOp() would cause it to error. Also adds e2e tests for currentoOp

Reproduction

Running

db.coll.insertOne({})
db.coll.find({$where: function() { sleep(20000) }}).projection({re: BSONRegExp('^(?i)\\Qchho0842\\E')})

and then concurrently in a different shell

db.currentOp()

would cause

Uncaught:
SyntaxError: Invalid regular expression: /^(?i)\Qchho0842\E/: Invalid group 

[gagik]

I realize CI isn't passing but I have trouble tracking down anything related to my change (and I know some tests have always been flakey), let me know if there's some way I can access better logs.

[gagik]

Remaining failing CI tests seem unrelated to the changes with exception to 1 MacOS test which should be fixed with a higher timeout 🤞

[kraenhansen]

👍 Nothing blocking.

[gagik]

Rest of the failing tests are not related to the changes, going ahead.