DOC: Replace pandas logo with a conditional image for light and dark …
...themes

Replaced the static pandas logo with a `picture` tag that displays a different logo based on the color scheme. In light mode, the original logo is shown, while in dark mode, a white version of the logo is displayed for better visibility.

In GitHub Dark Theme
![image](https://github.com/pandas-dev/pandas/assets/61258323/a820a065-29d9-489a-b6f8-1e9d68bb5e57)

In GitHub Light Theme
![image](https://github.com/pandas-dev/pandas/assets/61258323/66ff39ee-8f6f-4271-9cf6-16d7ba229717)

Thank you for the feedback, I'm glad you found the change helpful! 
Looking forward to do more contributions! Thanks @LakshmanKishore 