feat: add Mock method to ftl.Map #4145

Job	Run time
Test Go	2m 48s
Test README	1m 57s
Rebuild All	1m 42s
Console	54s
VSCode Extension	45s
Shard Integration Tests	5s
Lint	56s
Proto Breaking Change Check	5s
SQL	56s
Integration Test (TestServiceWithRealDal)	2m 22s
Integration Test (TestCron)	2m 37s
Integration Test (TestFSM)	3m 8s
Integration Test (TestFSMRetry)	3m 14s
Integration Test (TestFSMGoTests)	2m 55s
Integration Test (TestHttpIngress)	2m 53s
Integration Test (TestLease)	2m 52s
Integration Test (TestPubSub)	3m 31s
Integration Test (TestDatabase)	2m 56s
Integration Test (TestASMWorkflow)	2m 18s
Integration Test (TestASMPagination)	2m 21s
Integration Test (TestCmdsCreateProjectTomlFilesIfNonexistent)	2m 35s
Integration Test (TestNonExportedDecls)	2m 58s
Integration Test (TestUndefinedExportedDecls)	3m 2s
Integration Test (TestHttpEncodeOmitempty)	2m 59s
Integration Test (TestLifecycle)	3m 2s
Integration Test (TestInterModuleCall)	3m 21s
Integration Test (TestSchemaGenerate)	2m 51s
Integration Test (TestModuleUnitTests)	3m 16s
Integration Test (TestFTLMap)	3m 4s
Integration Test (TestRuntimeReflection)	2m 46s
Integration Success	1s
	1h 11m 10s

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