getLastError command should be marked as deprecated in 5.0

In 5.0 under SERVER-55788 we deprecated both the legacy op codes (OP_QUERY, OP_INSERT, etc.) and the getLastError command. This change was documented by DOCSP-10230 in https://github.com/mongodb/docs/commit/01d8caeb11fd2069fa8b305aed5c1f99a1e06e48. However, we forgot to make any changes related to getLastError in this commit!

We should do the following under this ticket:

• Add a note that getLastError is deprecated to the getLastError reference pages:
  • https://docs.mongodb.com/manual/reference/command/getLastError/
  • https://docs.mongodb.com/manual/reference/method/db.getLastError/
• Include a note about getLastError in the 5.0 compatibility changes page:
  • https://docs.mongodb.com/v5.0/release-notes/5.0-compatibility/#deprecated-wire-protocol-opcodes