Fix regex pattern for doublet detection tool options in nextflow_schema.json

Author: KurayiChawatama

nextflow_schema.json

@@ -106,7 +106,7 @@
                     "default": "scrublet",
                     "description": "Specify the tools to use for doublet detection. Setting to 'none' will skip this step",
                     "help_text": "If you want to use multiple tools, separate them with a comma. Available methods are: solo, scrublet, doubletdetection, scds, scdblfinder",
-                    "pattern": "^(none|((solo|scrublet|doubletdetection|scds|scdblfinder)?,?)*[^,]+$)"
+                    "pattern": "^(none|(solo|scrublet|doubletdetection|scds|scdblfinder)(,(solo|scrublet|doubletdetection|scds|scdblfinder))*)$"
                 },
                 "doublet_detection_threshold": {
                     "type": "integer",