[CLI] fix a few things in domain migration command (uber#5374)

What changed?

add two methods in ClientFactory for migration
countWorkflowCheck should be on current domain
fix concurrency bug
make template look slightly better
Why?

add two methods in ClientFactory for migration
This is needed to be able to use environment flags for internal usage

How did you test it?

shengs@shengs-C02XN3VDJGH6 cadence % go run cmd/tools/cli/main.go --do domain-1 domain migration --destination_address localhost:7933 --destination_domain domain-2 --tasklist ts1 --search_attr someID:INT
2023/08/08 10:21:28 Loading configFiles=[config/base.yaml config/development.yaml]
2023/08/08 10:21:28 Loading configFiles=[config/base.yaml config/development.yaml]
{"level":"info","ts":"2023-08-08T10:21:28.241-0700","msg":"Updated dynamic config","logging-call-at":"file_based_client.go:284"}
Validation Check:
- Domain Meta Data: true
    Current Domain:
      Name: domain-1
      UUID: d3cc0a3c-8f55-40af-9820-c48f8a0f46e5
    New Domain:
      Name: domain-2
      UUID: 203f0088-1d0f-40ac-a7c3-fdcf57ec0a99
- Workflow Check: true
    Long Running Workflow Num: 0
- Dynamic Config Check: false
    - Config Key: matching.asyncTaskDispatchTimeout
        Current Response:
          Data: "50s"
          Filters:
            - Name: domainName
              Value: "domain-1"
            - Name: taskListName
              Value: ["ts1"]
        New Response:
          Data: "20s"
          Filters:
            - Name: domainName
              Value: "domain-2"
            - Name: taskListName
              Value: ["ts1"]
- Search Attributes Check: false
    Missing Search Attributes in Current Domain:
      - someID:INT
    Missing Search Attributes in New Domain:
      - someID:INT
Potential risks

No Risk

tools/cli/app_test.go

@@ -60,6 +60,14 @@ func (m *clientFactoryMock) ServerAdminClient(c *cli.Context) admin.Client {
 	return m.serverAdminClient
 }
 
+func (m *clientFactoryMock) ServerFrontendClientForMigration(c *cli.Context) frontend.Client {
+	panic("not implemented")
+}
+
+func (m *clientFactoryMock) ServerAdminClientForMigration(c *cli.Context) admin.Client {
+	panic("not implemented")
+}
+
 func (m *clientFactoryMock) ElasticSearchClient(c *cli.Context) *elastic.Client {
 	panic("not implemented")
 }

tools/cli/domain.go

@@ -83,14 +83,13 @@ func newDomainCommands() []cli.Command {
 				newDomainCLI(c, false).DescribeDomain(c)
 			},
 		},
-
 		{
 			Name:    "migration",
 			Aliases: []string{"mi"},
 			Usage:   "Migrate existing domain to new domain. This command only validates the settings. It does not perform actual data migration",
 			Flags:   migrateDomainFlags,
 			Action: func(c *cli.Context) {
-				newDomainCLI(c, true).MigrateDomain(c)
+				newDomainMigrationCLIImpl(c).Validation(c)
 			},
 		},
 	}