Remove sample solution to Python programming exercise

[stackeduary]

On https://bitcoindevs.xyz/decoding/bitcoin-opcodes, the Python programming exercise has a sample solution that makes it pointless to even try the exercise, whereas, the JavaScript exercise does not.

Remove the sample solution so users can try it themselves first.

[deadmanoz]

This is also an issue for the P2PKH - Hard Python programming exercise. The solution is the only content of the exercise :)

[IgnacioPorte]

I didn't find where is the issue, is it already solved?

[jrakibi]

I removed the code related to the exercises in the markdown to test something. I'll add it back now so you can take a look