Two animation-related bugs in PPTX

[guojia99]

Two animation-related bugs in PPTX

GIF images embedded in the presentation cannot be played correctly and are converted to PNG images instead.
When a slide contains multiple animations, they are merged into a single playback action. The animations may need to be separated and played independently according to their original sequence and timing.

PPTx 2个动画方面的bug

1. 插图为GIF图片无法正确播放，会被转换为PNG
2. 一个页面有多个动画时，会被合并为一次播放动作，可能需要做一些拆分。