remove pickle_id column (and other related stuff?)

[dstandish]

Body

i don't think anyone uses dag pickling, and i think it's going to need to be removed for 3.0

Committer

• I acknowledge that I am a maintainer/committer of the Apache Airflow project.

[potiuk]

YES

[eladkal]

@dstandish is this something we still plan for AF3?

[ashb]

Closed by #43667