Change animation frames (#3627)

## Description
- Changes animation frames to be smaller
- Cleans up file names and popup logic

## tests
- Passes local CI

codex-rs/tui/frames/slug/frame_21.txt

@@ -0,0 +1,17 @@
+                                      
+             ddtotootottdd            
+          ttpeeddtxoxtcde-ptd         
+        cpddtpdge     edxptdept       
+      tpecgp             dtcptcpt     
+     5t5pe             te5do ooddt    
+    5g5e             tppd55    oodt   
+    epee           dg5et5p     ocog   
+     eo            oc get       e e   
+    e e  ttcccccttt  detget    c5 e   
+    e xo ed      dte   dgepet  5g-5   
+     c g- eeggg  pe     ppdtc 5e t    
+     pt ccd                 dpg 5     
+       pd  d-d          d-cpp te      
+         pod pgptcxxccopgg  -e        
+            pttctddddtdctpe           
+