[CAL][11] - Implement ExecutedMessages for chain accessor

[ogtownsend]

core ref: ca59d76a6e99c833e229c3eb9fc1c0f6c328f3c8

• Migrates and implements ExecutedMessages() in DefaultAccessor
• For more context, see NONEVM-1865

Stack:

1. [CAL][1] - Add initial CAL scaffolding to CCIPReader with legacy accessor #978
2. [CAL][2] - Implement Metadata() and GetContractAddress() #980
3. [CAL][3] - Implement GetChainFeeComponents #985
4. [CAL][4] - Implement MsgsBetweenSeqNums() function in accessor #987
5. [CAL][5] - implement LatestMsgSeqNum #988
6. [CAL][6] - move SourceChainConfig to chainaccessor types #989
7. [CAL][7] - implement GetExpectedNextSequenceNumber #990
8. [CAL][8] - Some minor cleanup and renaming #999
9. [CAL][9] - Implement CommitReportsGTETimestamp, GetTokenPriceUSD, and GetLatestPriceSeqNr #1000
10. [CAL][10] - Implement Nonces and GetChainFeePriceUpdate #1014
11. ➡️ [CAL][11] - Implement ExecutedMessages for chain accessor #1017

[ogtownsend]

I think we should leave this as map[ChainSelector][]SeqNumRange. Requiring only one range per chain seems odd?

[github-actions]

Metric	ogt/cal-11-implement-ExecutedMessages	main
Coverage	70.0%	69.9%