Improve UX for CLI scan modal

When there is no Access Token for the repository yet, the user is not guided well enough through the workflow.

The "Create Repository Access Token" button does not appear clearly enough as a button, it looks almost like it might be a headline, and is not clickable until an expiration date has been set on the left component, which was not explained in the text above.

Setting the expiration date for the token here manually is unnecessary anyway.

• Just make the token expire in 30 days by default, remove the date component
• Make the "Create Repository Access Token" button more clearly a button
• Make the workflow more clear, that a token is necessary and only once one is created or chosen, it will be added automatically to the CLI command below and only then the command works
• Fix grammar ("a" instead of "an" repository access token)
• (Optional) When navigating from /Code Risks, clicking Identify Risks and opening the modal by selecting DevGuard CLI and clicking continue, the modal should already open with Source Code Vulnerabilities selected on the bottom. It currently always defaults to Dependency Vulnerabilities being selected, but when the user checks their Code Risks and wants to do another SAST scan, he might just copy-paste the CLI command on the bottom without noticing he needs to switch to Source Code Vulnerabilities. Making the pre-selected command on the bottom be dependent on the path would be better UX.