Remove rule exclusions from eslint.config.js

[Eddasol]

Describe the improvement you would like to see
The current implementation (as of #1900) of eslint.config.js has turned of several rules as the current frontend implementation isn't complying with those rules.

Remove the exclusions from the recommended rules and solve the related issues.

Remove these:

• "react/react-in-jsx-scope": "off",
• "react/no-unescaped-entities": "off",
• "react/display-name": "off",
• "@typescript-eslint/no-unused-expressions": "off",
• "@typescript-eslint/no-explicit-any": "off",
• "@typescript-eslint/no-unused-vars": "off",
• "@typescript-eslint/no-non-null-asserted-optional-chain": "off",

How will this change existing functionality?
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How will this improvement affect the current Threat Model?
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