feat: upgrade to Typescript 5

[jsalvata]

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📚 Context/Description Behind The Change

Upgrade to Typescript 5.

🚨 Potential Risks & What To Monitor After Deployment

None perceived.

🧑‍🔬 How Has This Been Tested?

• npm-linked on a TS5 package which was throwing Parsing error: Invalid value for lib provided: es2022 errors.
• npm-linked on app (which is TS4) and checked linting works.

🚚 Release Plan

Merge.

[jsalvata]

Tested in app using npm install --save-dev eslint-config-mixmax@latest.
Works well (lint throws 30-something errors, but they are legitimate, caused by some previous change).