lambda-promtail should have an option to remove cw log group name from labels

[gkaskonas]

Is your feature request related to a problem? Please describe.
Having lo group name as a label creates too many labels when running thousands of different lambda functions

Describe the solution you'd like
An environment variable that can be passed as a boolean

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[cstyan]

Not sure how you would identify logs from a specific function otherwise, but this should be possible via #10755, please let us know if that feature doesn't work for you.