front: turn on @typescript-eslint/no-unnecessary-type-assertion lint

First part of #8772

Enable typed hinting so that ESLint has information about types
and can provide more feedback. Only enable a single typed lint
rule for now (rest will be a lot more work to fix).

The rule @typescript-eslint/no-unnecessary-type-assertion prevents
unnecessary type assertions (casting a string to a string).
Reducing type assertions is nice because type assertions override
type checking and thus may hide type mismatches.

Signed-off-by: Simon Ser <[email protected]>

front/.eslintrc

@@ -11,11 +11,13 @@
     "airbnb",
     "plugin:import/recommended",
     "plugin:import/typescript",
-    "prettier"
+    "prettier",
+    "plugin:@typescript-eslint/base"
   ],
   "plugins": ["import", "only-warn", "prettier", "react", "react-hooks", "vitest"],
   "parserOptions": {
-    "ecmaVersion": "latest"
+    "ecmaVersion": "latest",
+    "project": true
   },
   "rules": {
     "import/order": [
@@ -41,6 +43,7 @@
     "@typescript-eslint/consistent-type-imports": ["error", { "fixStyle": "inline-type-imports" }],
     "@typescript-eslint/no-shadow": "error",
     "@typescript-eslint/no-use-before-define": "error",
+    "@typescript-eslint/no-unnecessary-type-assertion": "error",
 
     "@typescript-eslint/ban-types": [
       "error",