Add support for Soroban external calls 🎉 #7040

Job	Run time
Container Image	12m 4s
Docs	1m 39s
Linux Arm	19m 23s
Linux x86-64	36m 39s
Mac Intel	1s
Mac Arm	11m 10s
Stdlib	2m 21s
Repolinter	1m 3s
Windows	9m 59s
Mac Universal Binary	0s
Polkadot Integration test with subxt	0s
Polkadot Integration test	0s
Solana Integration test	0s
Anchor Integration test	0s
Soroban Integration test	0s
Visual Code Extension	0s
Coverage report	0s
	1h 34m 19s

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