fix(#5131): Accurate resource open check when using log file handle

[Deltik]

Motivation and Context

Fixes: https://github.com/e107inc/e107/issues/5131

Description

Switch the logging file handle check to use is_resource() for correctly identifying whether the file handle is open.

How Has This Been Tested?

New unit test: e107EmailTest::testLogFileHandle()

Types of Changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Performance enhancement (non-breaking change which improves efficiency)
• [ ] Code cleanup (non-breaking change which makes code smaller or more readable)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation (a change to man pages or other documentation)

Checklist

• [x] My code adheres to the e107 code style standard.
• [x] I have read the contributing document.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests pass.

[codeclimate[bot]]

Code Climate has analyzed commit 688ebdfe and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (80% is the threshold).

This pull request will bring the total coverage in the repository to 38.7% (-0.1% change).

View more on Code Climate.

[CaMer0n]

Great! Thank you @Deltik ! 👍