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

[Deltik]

Motivation and Context

Fixes: #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

• 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

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

[codeclimate]

Code Climate has analyzed commit 688ebdf 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 ! 👍