Support CasEvac CoTs with multiple ZMISTs

[brian7704]

CasEvac CoTs can have multiple ZMIST tags. cot_controller.py currently assumes there is only one.

<event access="Undefined" how="h-g-i-g-o" stale="2025-08-22T17:17:47.492Z" start="2024-08-22T17:17:47.492Z" time="2024-08-22T17:17:47.492Z" type="b-r-f-h-c" uid="57ec447d-cbc6-46a3-958a-756212ee3101" version="2.0">
	<point ce="9999999.0" hae="9999999.0" lat="41.9190724" le="9999999.0" lon="-93.2959722"/>
	<detail>
		<status readiness="false"/>
		<archive/>
		<contact callsign="HALIBUT"/>
		<precisionlocation altsrc="???"/>
		<link parent_callsign="HALIBUT" production_time="2024-08-22T17:16:07.558Z" relation="p-p" type="a-f-G-U-C" uid="ANDROID-22ca91fe4df4d567"/>
		<archive/>
		<color argb="-1"/>
		<_medevac_ casevac="false" child="1" epw="1" equipment_none="true" freq="0.0" friendlies="you fjfj" hlz_marking="2" hlz_remarks="tzjvmn" medline_remarks="Hfhvj" nonus_military="1" security="2" terrain_loose="true" terrain_rough="true" title="MED.22.131607" us_military="1" winds_are_from="jckvlb" zone_prot_selection="0">
			<zMistsMap>
				<zMist i="Deformity Bleeding" m="Frag Multiple Heat" s="Pulse Radial: No Radial Skin: Warm/Moist Airway: No Airway" t="ufiglb" title="ZMIST2" z="kgxkck"/>
				<zMist i="Bleeding Avulsion Puncture" m="Crush Fall/MVA" s="Pulse Strength: Strong/Steady" t="jcufi" title="ZMIST1" z="hfhch"/>
			</zMistsMap>
		</_medevac_>
	</detail>
</event>