Feature Request - Allow inject to run with missing references

Let's assume there is a config template like `.env.template` which I want to share with my team. This could be in a git repo that is committed as part of a code base. To run all of the tests you would need all of the env vars defined but to run a subset of the tests this isn't necessary (think unit, app and int tests).

# .env.template file
# SQL - Everyone has this access
SQL_PASSWORD={{ op://User/sql/password }}
SQL_USER={{ op://User/sql/user }}

# AWS S3 - Only some people have/need to run these integration tests
# aws/password doesn't exist in this user's 1password
AWS_PASSWORD={{ op://User/aws/password }}
AWS_USER={{ op://User/aws/user }}

Now run `inject`:

op inject -i .env.template -o .env -f

[ERROR] 2025/07/02 13:38:51 could not resolve item UUID for item aws: could not find item aws in vault ...

It would be very beneficial to have a flag that ignores missing:

op inject -i .env.template -o .env -f -ignore-missing

# .env file
# SQL - Everyone has this access
SQL_PASSWORD=abcdef
SQL_USER=me

# AWS S3 - Only some people have/need to run these integration tests
# aws/password doesn't exist in this user's 1password
AWS_PASSWORD=
AWS_USER=

This would really help with 1Password adoption across my team.