fix(load_plugins): prevent hexo-theme being loaded as plugin (#4592)

lib/hexo/load_plugins.js

@@ -12,16 +12,6 @@ module.exports = ctx => {
 };
 
 function loadModuleList(ctx) {
-  let customThemeName;
-
-  if (ctx.config) {
-    const { theme } = ctx.config;
-
-    if (theme) {
-      customThemeName = String(theme);
-    }
-  }
-
   const packagePath = join(ctx.base_dir, 'package.json');
 
   // Make sure package.json exists
@@ -37,12 +27,12 @@ function loadModuleList(ctx) {
       return deps.concat(devDeps);
     });
   }).filter(name => {
-    // Ignore plugin whose name endswith "hexo-theme-[ctx.config.theme]"
-    if (name.endsWith(`hexo-theme-${customThemeName}`)) return false;
-
     // Ignore plugins whose name is not started with "hexo-"
     if (!/^hexo-|^@[^/]+\/hexo-/.test(name)) return false;
 
+    // Ignore plugin whose name is started with "hexo-theme"
+    if (/^hexo-theme-|^@[^/]+\/hexo-theme-/.test(name)) return false;
+
     // Ignore typescript definition file that is started with "@types/"
     if (name.startsWith('@types/')) return false;