chore: improve slow tests

- Optimize generting random files.
- Reduce big file of 128MiB to 32MiB (git was never made for large files
anyways, but simply tests that it works).
- Reduce looped git operations from 100 iterations to 10.
- Add extra print statements to know what a slow test is doing, this
also helps to see if a particular piece of code in a slow test is the
culprit or if the test is just very extensive.
- Set `[ui.notification].EVENT_SOURCE_UPDATE_TIME` to 1s to speed up
`TestEventSourceManagerRun`.
- Sneaked in some general test improvements.

tests/integration/user_count_test.go

@@ -98,6 +98,7 @@ func (countTest *userCountTest) getCount(doc *goquery.Document, name string) (in
 
 func (countTest *userCountTest) TestPage(t *testing.T, page string, orgLink bool) {
 	t.Run(page, func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
 		var userLink string
 
 		if orgLink {