Improve expiring cert task language to avoid misleading replacement window

[aduth]

🛠 Summary of changes

Updates messaging displayed as the output of the rake print_expiring task to improve clarity.

The intent of the message is to explain the window of time which was checked for an expiring certificate.

The concern is that the message may mislead a reader into thinking that the listed certificates can be replaced by that time, even if the actual expiration is sooner.

[aduth]

The failing build appears to be related to the known expiring certificate, tracked in LG-12045.

Conveniently, it also serves as nice validation of these changes 😄

Found certs expiring between now and 2024-02-10 13:52:58 UTC
- Expiration: 2024-01-21 14:38:10 UTC
  Subject: /C=US/O=ORC PKI/CN=ORC SSP 4
  Issuer: /C=US/O=U.S. Government/OU=FPKI/CN=Federal Common Policy CA G2
  Key ID: 14:0B:99:1F:98:1F:64:8C:6F:C3:FF:7A:D5:FF:F5:F8:4E:49:9C:21

[aduth]

Merging bypassing failing build, based on explanation at #418 (comment).