error_retry label not recognized as standard label for certain module structures

Description of the bug

Running nf-core lint on certain pipelines returns Non-standard labels found: error_retry even though the error_retry label is defined in conf/base.conf.
This behaviour only appears when the modules that have the error_retry label are structured as single .nf file in the modules directory (e.g. modules/local/force-mosaic.nf).
The warning does not appear for modules that are structured using a directory that contains a main.nf file (e.g. modules/local/force-mosaic/main.nf).
An example where this behaviour appears is the rangeland pipeline.

Command used and terminal output

$ nf-core lint

│ force-higher_level              │ modules/local/force-higher_level.nf             │ Non-standard labels found: error_retry                                             │
│ force-preprocess                │ modules/local/force-preprocess.nf               │ Non-standard labels found: error_retry                                             │
│ higher_level_force_config       │ modules/local/higher_level_force_config.nf      │ Non-standard labels found: error_retry                                             │
│ merge                           │ modules/local/merge.nf                          │ Non-standard labels found: error_retry                                             │
│ preprocess_force_config         │ modules/local/preprocess_force_config.nf        │ Non-standard labels found: error_retry

System information

nextflow version 24.04.4.5917
nf-core/tools version 2.14.1
Local executor on Ubuntu Linux

Start by reproducing the report with nf-core lint against a pipeline containing modules/local/force-mosaic.nf and modules/local/force-mosaic/main.nf, using error_retry in conf/base.conf. Trace how lint discovers labels for each module structure, then verify that defined error_retry is accepted for both forms while genuinely unknown labels remain reported.