Update IRS2 reference files to address alternating column noise

[stscijgbot-jp]

Issue JP-3611 was created on JIRA by Melanie Clarke:

Ticket JP-3437 implemented a partial fix for residual alternating column noise (ACN) and amplifier offsets in NIRSpec IRS2 mode.  The fix is to subtract a per-amplifier reference pixel offset, respecting detector column even/odd parity, prior to performing IRS2 corrections.  This change is off by default, however, because while it sometimes improves residual ACN when turned on, it also sometimes introduces ACN, making some images worse.  

We'd like to investigate whether removing the static alternating column handling in the existing IRS2 reference files would improve this fix and enable turning it on by default.

[stscijgbot-jp]

Comment by Melanie Clarke on JIRA:

Eddie Bergeron - remaining IRS2 reference file work from JP-3437 is now being tracked in this ticket.