6.0.x: content: don't error out on incomplete hex - v2

[jasonish]

Before 6.0.6 if hex content was incomplete, Suricata didn't error out. With 6.0.6 incomplete hex was detected and errored on which is a breaking change in a release branch. Instead, only emit a warning unless strict content checking has been requested.

To enable strict behaviour on incomplete content hex in a rule, "--strict-rule-keywords=content" can be used on the command line.

Issue: https://redmine.openinfosecfoundation.org/issues/5546

For now there is no accompanying master commit, as the change in behaviour for a major version is OK.

Previous PR: https://github.com/OISF/suricata/pull/7885

Changes from last PR:

• Better error handing. In non-strict mode an error with context will be displayed, but not result in a test failure unless strict mode is requested.
• Log error if strict mode is enabled, not a warning.
• Add this warn/error checking to all users of content parsing.

suricata-verify-pr: 942

[suricata-qa]

Information: QA ran without warnings.

Pipeline 9372