.eslintrc.json: remove second eslint-plugin-jsonc

This seems to have been added twice at some point.

(cherry picked from commit 9896eab)

Author: alanorth

.eslintrc.json

@@ -12,7 +12,6 @@
     "eslint-plugin-rxjs",
     "eslint-plugin-simple-import-sort",
     "eslint-plugin-import-newlines",
-    "eslint-plugin-jsonc",
     "dspace-angular-ts",
     "dspace-angular-html"
   ],