make id flag mandatory for bridge-auth-config command'

[boddumanohar]

A brief description of the changes in this PR:

fixes: #167

Tasks to complete before merging PR:

• Ensure system tests are passing. If not Run them manually to check for any regressions 📋
• Do any new system tests need added to test this change? do any existing system tests need updated? If so create a PR at 0chain/system_test
• Merge your system tests PR to master AFTER merging this PR

Associated PRs (Link as appropriate):

• blobber:
• gosdk:
• system_test:
• zboxcli:
• 0chain:
• Other: ...

[dabasov]

lgtm

[service-0chain]

Manual system tests [success] with the following config

config	value
tests skipped	YES
system-tests	master
gosdk	NOT OVERRIDDEN
zboxcli	staging
zwalletcli	bridge-auth-config-fix
0chain	staging
blobber	staging
authorizer	staging
0box	staging
0block	staging
0dns	staging
explorer	staging
0proxy	staging
0search	staging