Updated Codecov action and removed token

[mandreko-bitwarden]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/VULN-127

📔 Objective

Codecov updated the codecov/codecov-action GitHub action. In this new version, it no longer requires a CODECOV_TOKEN in the workflows. This PR will update the action to t
he current latest version (5.1.2) and remove the CODECOV_TOKEN for the action.

Note: The codecov/test-results-action GitHub action still requires a token, and can not be removed yet.

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes

[AmyLGalles]

Undid my review when I saw that it requires a new action, do you need help adding a new action to the approved list?