Fixes / Misc

• Fixed mission 30 "Singularity" crash.
• Fixed mission 26 "Capitulation" crash.
• Fixed mission 31 "Foothold" failing incorrectly.
• Fixed 3rd/4th prologue missions not being marked as completed.
• Fixed broken reveal trigger in Prologue iii.
• Fixed potential crash on mission 13 "Abasement".
• Fixed potential crash on mission 35 "Purification".
• Fixed Apprehension not failing after losing all units.
• Prevent Scrin allies from destroying rebel Signal Transmitters in Annexation.
• Fixed Annexation briefing typo.
• Fixed Tank Destroyer being shown (but never being available) when playing on low tech level.