mrhlpr.json: remove (MR 6284)

The regex has not been working for a long while, there have been
previous attempts to try fix it, but it's still failing. There is
also common understanding in the team, that the regex is not terribly
useful. So remove it.

.mrhlpr.json

@@ -1,10 +0,0 @@
-{
-    "subject_format": {
-        "pass": [
-            "^(([a-z]+\\/\\)?\\([a-z\\-0-9*{}]+),?)+: [a-z][A-Za-z\\/\\-0-9*{}\\.,_&:=' ]+( \\(MR \\d+\\)|)$",
-            "^CI: [a-z-0-9*{}\\(\\)\\.,_ ][A-Za-z\\/\\-0-9*{}\\.,_ ]+( \\(MR \\d+\\)|)$",
-            "^mrhlpr.json: [a-z-0-9*{}\\(\\)\\.,_ ][A-Za-z\\/\\-0-9*{}\\.,_ ]+( \\(MR \\d+\\)|)$",
-            "^pmaports.cfg: [a-z-0-9*{}\\(\\)\\.,_ ][A-Za-z\\/\\-0-9*{}\\.,_ ]+( \\(MR \\d+\\)|)$"
-        ]
-    }
-}