Ledger Channels must be initiated in order

[lalexgap]

    To co-ordinate who initiates the ledger channel between two hubs I've introduced a simple rule: The participant with the lowest sequence number of the two hubs is responsible for creating the ledger channel.

It seems that the intermediaries need to passed in the correct order, based on the ledger initiator (I think?).
Since we use the sequence number to determine who initiates ledger channels we can just sort the intermediaries we pass in by their sequence number.

If I don't do this I get this error:

[0m panic: 0xA73B1683e0FCD74CEFF77aA5A90cAE1cF52d1c0F, error in run loop: signed proposal is not addressed to a known ledger connection {Signature:{R:[92 99 4 159 107 148 113 183 88 34 206 249 199 58 188 66 200 68 183 34 223 59 233 114 212 234 215 169 34 23 226 41] S:[123 131 214 254 250 117 65 42 222 212 113 236 31 15 36 251 243 88 198 162 117 13 215 51 6 198 227 98 105 176 200 126] V:28} Proposal:{LedgerID:0x1db0ab987f97ca8d2d21845016ebe74996102fb884b78c77efb88739a0b069c0 ToAdd:{Guarantee:{amount:<nil> target:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] left:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] right:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]} LeftDeposit:<nil>} ToRemove:{Target:0x6d8536f70e580266089f52475b49a95d97bed033b94a516b02a16803242e24f2 LeftAmount:+9999995628}} TurnNum:4}

Originally posted by @lalexgap in statechannels/go-nitro-testground#132 (comment)