Make firemaking skillcape a valid light source for the giant mole

What has been done in this MR?

• Made it possible to enter the giant mole cave with the firemaking skillcape perk as your only light source
• Made you immune to the mud splash attack effect in this case, since the skillcape should not count as an open light source -- On second thought, this was not necessary, as this is already handled properly owing to the fact that the firemaking cape doesn't match getActiveLightSource anyway.

What should testers check?

• That you can enter the giant mole with just the firemaking skillcape perk

• I have tested these changes thoroughly.
• I used the relevant Thanos/Zaros tool for any JSON edits where possible, and have attached screenshots of any changes.