Match enemy portrait lookup and link value accessor

[loserkidsblink]

Complete the remaining mismatch in emExternalValueAccesser::getFaceTexPtr and link em_external_value_accesser.cpp as matching.

Use explicit branches for the missing-weapon fallback and assign the weapon's portrait selector before calling Enemy::getFaceTexPtr. This removes the extra register copy and reproduces the original instruction sequence.

This adds one newly matched function (132 bytes) and enables the existing 11-function unit (916 bytes) to be linked from C++. The other functions were already matching.

Validation on RSBE01_02:

• ninja: all 127 output files pass the original SHA-1 checks.
• Objdiff: all 11 functions match at 100%; the unit is marked complete and linked.
• git diff --check: passes.

[decomp-dev]

Report for RSBE01_02 (f168bd9 - 2e20389)

📈 Matched code: 1.20% (+0.00%, +132 bytes)
📈 Linked code: 1.02% (+0.01%, +916 bytes)

✅ 1 new match

Unit	Item	Bytes	Before	After
sora_enemy/mo_enemy/sora_enemy/em_external_value_accesser	emExternalValueAccesser::getFaceTexPtr(Enemy*, unsigned long)	+13	90.76%	100.00%