fix: define base uri for login v2 feature as string to make it config… (#10533)

…urable

# Which Problems Are Solved

BaseURI defined in environment variables or configuration files was
ignored for Login v2 feature flag.

# How the Problems Are Solved

Define BaseURI as string so that the environment variables and
configuration files can be parsed into it.

# Additional Changes

None

# Additional Context

Closes #10405

cmd/setup/config_test.go

@@ -37,6 +37,9 @@ DefaultInstance:
   Features:
     LoginDefaultOrg: true
     UserSchema: true
+    LoginV2:
+      Required: true
+      BaseURI: 'http://zitadel:8080'
 Log:
   Level: info
 Actions:
@@ -44,9 +47,13 @@ Actions:
     DenyList: []
 `},
 		want: func(t *testing.T, config *Config) {
-			assert.Equal(t, config.DefaultInstance.Features, &command.InstanceFeatures{
+			assert.Equal(t, config.DefaultInstance.Features, &command.InstanceSetupFeatures{
 				LoginDefaultOrg: gu.Ptr(true),
 				UserSchema:      gu.Ptr(true),
+				LoginV2: &command.InstanceSetupFeatureLoginV2{
+					Required: true,
+					BaseURI:  gu.Ptr("http://zitadel:8080"),
+				},
 			})
 		},
 	}, {