Revert "fix panic on closing a tab"

This reverts commit d7feb56cbe.

This commit introduced a regression in which upon closing any but the
last tab caused an out of range panic would occur.

Steps to reproduce
- open a tab
- open another tab
- close the first tab

Fixes: https://todo.sr.ht/~rjarry/aerc/58
Reported-by: akspecs <akspecs@gmail.com>
Signed-off-by: Moritz Poldrack <git@moritz.sh>
Acked-by: Robin Jarry <robin@jarry.cc>

lib/ui/tab.go

@@ -74,13 +74,10 @@ func (tabs *Tabs) invalidateChild(d Drawable) {
 
 func (tabs *Tabs) Remove(content Drawable) {
 	indexToRemove := -1
-	removeTab := func() {}
 	for i, tab := range tabs.Tabs {
 		if tab.Content == content {
-			removeTab = func() {
-				tabs.Tabs = append(tabs.Tabs[:i], tabs.Tabs[i+1:]...)
-				tabs.removeHistory(i)
-			}
+			tabs.Tabs = append(tabs.Tabs[:i], tabs.Tabs[i+1:]...)
+			tabs.removeHistory(i)
 			indexToRemove = i
 			break
 		}
@@ -102,7 +99,6 @@ func (tabs *Tabs) Remove(content Drawable) {
 		// selected tab is now one to the left of where it was
 		tabs.Selected--
 	}
-	removeTab()
 	tabs.TabStrip.Invalidate()
 }