Improve graph filter paging and loading

[justinrobots]

Description

When searching/filtering the graph and more than one page of results are returned, navigating to more history is not easy.

Navigating with up/down arrows works inconsistently.

• maybe add a "show more results" button at the bottom so it is clear that there is more to see. get rid of "infinite scroll" mode in this case?

[lexandrop]

Completely agree. Search/filter are the main features I use the "Commit Graph" for, and for large enough repos it feels unusable. Sometimes it's much faster and easier to find the commit I'm looking for manually in a sidebar, or via the "GitLens: Search commit" VSCode command.