fix(cli): fix the wrong graph in "gas log" when merging branches

When merging the left branch, the right branch also needs to move to the left
```
* 4c564ea (b3) 15
* a3f25ce 13
* ebb775e 8
| * 2da7d6e (b1) 14
| * aeac003 6
| | * 8c9e82e (main) 12
| | | * 1c22915 (b5) 11
| | |/
| |/|
| * | bec94e0 a
| | | * ef0e4c2 (b2) 10
| | | * dee8986 7
| | |/
| |/|
|/| |
* | | d7677e0 4
* | | e1d77c4 3
|/|
| | * f478341 (b4) 9
| |/
| * dc2a3cc 5
|/
* d0eeb20 2
* bce9056 1
```

tensorbay/cli/log.py

@@ -325,7 +325,10 @@ def _add_graph_oneline(
         # Merge branches.
         del self._layer_colors[self._merge_pointer]
         lines = [f"{self._get_title_prefix(prefixes, original_pointer)} {log}"]
-        lines.extend(f"{prefixes}\n" for prefixes in self._get_merge_prefixes())
+        lines.extend(
+            f"{prefixes}\n"
+            for prefixes in self._get_merge_prefixes(self._merge_pointer, self._pointer)
+        )
         return "".join(lines)
 
     def _add_graph_full(
@@ -342,21 +345,26 @@ def _add_graph_full(
         else:
             # Merge branches.
             del self._layer_colors[self._merge_pointer]
-            merge_prefixes = self._get_merge_prefixes()
+            merge_prefixes = self._get_merge_prefixes(self._merge_pointer, self._pointer)
             lines.extend(self._combine_details(list(merge_prefixes), list(splitlines)))
         return "".join(lines)
 
     def _get_colorful_prefixes(self) -> List[str]:
         return [click.style("|", fg=color) for color in self._layer_colors]
 
-    def _get_merge_prefixes(self) -> Iterator[str]:
+    def _get_merge_prefixes(self, merge_pointer: int, pointer: int) -> Iterator[str]:
         prefixes = []
         for color in self._layer_colors:
             prefixes.append(click.style("|", fg=color))
             prefixes.append(" ")
-        for i in range(self._merge_pointer, self._pointer, -1):  # type: ignore[arg-type]
+
+        for i in range(merge_pointer, pointer, -1):
             temp_prefixes = prefixes.copy()
-            temp_prefixes[2 * i - 1] = click.style("/", fg=self._layer_colors[self._pointer])
+            temp_prefixes[2 * i - 1] = click.style("/", fg=self._layer_colors[pointer])
+            if i == merge_pointer:
+                for j, color in enumerate(self._layer_colors[i:], i):
+                    temp_prefixes[2 * j] = " "
+                    temp_prefixes[2 * j + 1] = click.style("/", fg=color)
             yield "".join(temp_prefixes)
 
     @staticmethod