Fix: (ctrl+)b crash on new profile

[larswijn]

When pressing b with debug mode enabled (or ctrl+b with debugplus), the game instantly starts a new run. The modded SMODS.RunSelect.Functions.start_run has some issues compared to the vanilla Game:start_run implementation that this PR aims to fix:

1. On a fresh profile, pressing (ctrl+)b caused the new modded RunSelect to crash. I fixed it to fallback to Red Deck and White Stake, like the vanilla version.

2. While in the vanilla run select screen, pressing (ctrl+)b starts a run with the currently viewed deck. I modified the new modded RunSelect to also respect the currently viewed deck and stake.

What I have NOT fixed/changed but did notice:
Pressing (ctrl+)b while in a challenge run resets to an "empty" challenge deck on vanilla, and resets to red deck with RunSelect. Both of these are unexpected.

Additional Info:

• I didn't modify api's or I've made a PR to the wiki repo.
• I didn't modify api's or I've updated lsp definitions.
• I didn't make new lovely files or all new lovely files have appropriate priority.