Skip Melee in Firing Mode

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Summary

SUMMARY: Bugfixes "Fixes crashes involving bayonet type items"

Purpose of change

Fixes #35117 and Fixes #30676

Describe the solution

Reverted an erroneous change that broke the loading of gunmods.
Added extra logic to skip over melee gun modes when in the firing screen.

Describe alternatives you've considered

Automatically switch between reach_attack() targeting view and fire() targeting view.
Merge the two firing views.

Testing

Created a new character.
Spawned in a rifle.
Spawned in one of every bayonet type gunmod (combat knife, makeshift bayonet, etc.)
Tested that each can be installed as a gunmod on a rifle.
Spawned in ammo and a magazine for the rifle.
Tested switching firing modes both inside of and outside of the fire() targeting view.
Also tested that regular reach attacks still worked.

Additional context

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Checking if ammo_modifier is empty is sufficient for all gunmods now that all gunmod items actually have def.mod instantiated, and makes sure that any gunmod which isn't itself a gun, but still modifies ammo, will work in the future (none exist currently)

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load_gunmod() Already calls both of these functions, as both are needed. This revert allows items which are not typed as GUNMOD to exhibit correct behavior.

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As mentioned in my code comment, load_gunmod() already calls both load_slot( islot_mod [...] ) and load_slot( islot_gunmod [...] ) so items which can be optional gunmods need to call both of those with load_slot_optional().

The resulting 'unvisited JSON' errors either need to be ignored, the entire def.gunmod and def.mod dichotomy needs to be fixed for non GUNMOD typed items, or no items should be usable as GUNMODs unless they are explicitly that type (no more combat knife bayonet).

[AMurkin]

Fixes #35117 and #30676

Rewrite it like so:
Fixes #35117 and Fixes #30676

[LetterShapedGlyphs]

Rewrite it like so:
Fixes #35117 and Fixes #30676

Ah, didn't realize the word "Fixes" was important. Thank you.

[snipercup]

Tested:

• spawned a m4a1 and a glock 17
• spawned some gunmods
• attached a combat knife to the m4a1
• removed the combat knife and added a sword bayonet to the m4a1
• attached pistol bayonet to the pistol
• switched firing modes (auto, semi auto) when in firing mode using the m4a1
• tested reach attack by spawning a blob and pressing tab while wielding my m4a1 2 tiles away
• tested firing the m4a1 normally using semi-auto and full auto

no crashes or errors.