Tweak eslint config, fix new issues (#35019)

1. Enable
[`@typescript-eslint/no-unnecessary-type-conversion`](https://typescript-eslint.io/rules/no-unnecessary-type-conversion/),
I think the two cases that were hit are safe cases.
2. Disable `no-new-func`, `@typescript-eslint/no-implied-eval` does the
same but better.

.eslintrc.cjs

@@ -326,6 +326,7 @@ module.exports = {
     '@typescript-eslint/no-unnecessary-type-arguments': [0],
     '@typescript-eslint/no-unnecessary-type-assertion': [2],
     '@typescript-eslint/no-unnecessary-type-constraint': [2],
+    '@typescript-eslint/no-unnecessary-type-conversion': [2],
     '@typescript-eslint/no-unsafe-argument': [0],
     '@typescript-eslint/no-unsafe-assignment': [0],
     '@typescript-eslint/no-unsafe-call': [0],
@@ -645,7 +646,7 @@ module.exports = {
     'no-multi-str': [2],
     'no-negated-condition': [0],
     'no-nested-ternary': [0],
-    'no-new-func': [2],
+    'no-new-func': [0], // handled by @typescript-eslint/no-implied-eval
     'no-new-native-nonconstructor': [2],
     'no-new-object': [2],
     'no-new-symbol': [2],