chore(codersdk): deprecate WorkspaceAppStatus.{NeedsUserAttention,Icon} (#17358)

https://github.com/coder/coder/pull/17163 introduced the
`workspace_app_statuses` table. Two of these fields
(`needs_user_attention`, `icon`) turned out to be surplus to
requirements.

- Removes columns `needs_user_attention` and `icon` from
`workspace_app_statuses`
- Marks the corresponding fields of `codersdk.WorkspaceAppStatus` as
deprecated.

codersdk/toolsdk/toolsdk_test.go

@@ -75,7 +75,6 @@ func TestTools(t *testing.T) {
 			"summary": "test summary",
 			"state":   "complete",
 			"link":    "https://example.com",
-			"emoji":   "✅",
 		})
 		require.NoError(t, err)
 	})