Add support for Soroban external calls 🎉 #7059

Job	Run time
Docs	1m 12s
Repolinter	12s
Container Image	11m 39s
Linux Arm	19m 16s
Linux x86-64	37m 51s
Mac Arm	10m 48s
Mac Intel	1s
Stdlib	8s
Windows	29m 4s
Mac Universal Binary	0s
Polkadot Integration test with subxt	0s
Anchor Integration test	0s
Solana Integration test	0s
Polkadot Integration test	0s
Soroban Integration test	0s
Visual Code Extension	0s
Coverage report	0s
	1h 50m 11s

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