gh-159102: Convert Tachyon 'Live mode' vidoes to mp4

Doc/library/profiling.sampling.rst

@@ -1312,9 +1312,10 @@ data, similar to the ``top`` command for system processes::
    python -m profiling.sampling run --live script.py
    python -m profiling.sampling attach --live 12345
 
-.. only:: not latex
+.. only:: html and not epub
 
-   .. figure:: tachyon-live-mode-2.gif
+   .. figure:: tachyon-live-mode-2.mp4
+      :class: controls no-scaled-link
       :alt: Tachyon live mode showing all threads
       :align: center
       :width: 100%
@@ -1337,9 +1338,10 @@ main table, showing instruction-level statistics for the currently selected
 function. This panel displays which bytecode instructions are executing most
 frequently, including specialized variants and their base opcodes.
 
-.. only:: not latex
+.. only:: html and not epub
 
-   .. figure:: tachyon-live-mode-1.gif
+   .. figure:: tachyon-live-mode-1.mp4
+      :class: controls no-scaled-link
       :alt: Tachyon live mode with opcode panel
       :align: center
       :width: 100%