refactor: plugin loading logic (#3448)

tsconfig.json

@@ -155,6 +155,9 @@
     {
       "path": "./tests/affine-local"
     },
+    {
+      "path": "./tests/affine-plugin"
+    },
     {
       "path": "./tests/affine-legacy/0.7.0-canary.18"
     }