Adds shaft miner to jobs available for FTU contractors (#6467)

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## About The Pull Request

Title

## Why It's Good For The Game

Why _can't_ the union bring in their miners?

## Changelog

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🆑
tweak: The Free Trade Union can now send in their miners and salvage contractors to do work for NanoTrasen.
/🆑

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code/modules/lore_hardcoded/faction.dm

@@ -106,6 +106,7 @@
 	job_whitelist = list(
 		JOB_ID_QUARTERMASTER,
 		JOB_ID_CARGO_TECHNICIAN,
+		JOB_ID_SHAFT_MINER,
 		JOB_ID_STATION_ENGINEER,
 		JOB_ID_PARAMEDIC,
 		JOB_ID_PILOT,