Reduce hit target of more memory loader

[colin-grant-work]

What it does

Fixes #134

The previous code didn't set the header wrapping div to be flex, and it didn't justify content itself, meaning that the 'more memory loader' took up the full width.

How to test

1. Confirm that the hit target of the more memory loader is limited to the text itself.

Alternatively, the more memory renderer could wrap itself so that it still took up the whole width, but only the text was the hit target. If this seems preferable, it can be implemented.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the contribution guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the code of conduct

[jreineckearm]

Thanks a lot, @colin-grant-work , for picking this up! @arekzaluski , could you please help with reviewing this one?

[arekzaluski]

LGTM. Issue is fixed. While testing it I spotted two other small issues. They however also exists on main so unrelated to this change.

1. There is no pointer cursor when hovering over the dropdown for selecting the number of bytes to load
2. Clicking the dropdown to select the ammount of bytes is automatically fetching more data. That should not be the case as user only selects the ammount of bytes to load at that point

[colin-grant-work]

@arekzaluski, good catches. I've made a new issue (#144) for those.