templates: add eslint ignore rule for '.next/' (#12332)

### What?
Standardizes ESLint configurations across all template projects like
website template to ensure consistent code quality enforcement.

### Why?
Previously, there were inconsistencies in the ESLint configurations
between different template projects. Some templates were missing the
.next/ ignore pattern, which could lead to unnecessary linting of build
files. By standardizing these configurations, we ensure consistent code
quality standards and developer experience across all template projects.

### How?
Added the missing ignores: ['.next/'] configuration to templates that
were missing it

templates/blank/eslint.config.mjs

@@ -30,6 +30,9 @@ const eslintConfig = [
       ],
     },
   },
+  {
+    ignores: ['.next/'],
+  },
 ]
 
 export default eslintConfig

templates/with-payload-cloud/eslint.config.mjs

@@ -30,6 +30,9 @@ const eslintConfig = [
       ],
     },
   },
+  {
+    ignores: ['.next/'],
+  },
 ]
 
 export default eslintConfig

templates/with-postgres/eslint.config.mjs

@@ -30,6 +30,9 @@ const eslintConfig = [
       ],
     },
   },
+  {
+    ignores: ['.next/'],
+  },
 ]
 
 export default eslintConfig

templates/with-vercel-mongodb/eslint.config.mjs

@@ -30,6 +30,9 @@ const eslintConfig = [
       ],
     },
   },
+  {
+    ignores: ['.next/'],
+  },
 ]
 
 export default eslintConfig

templates/with-vercel-postgres/eslint.config.mjs

@@ -30,6 +30,9 @@ const eslintConfig = [
       ],
     },
   },
+  {
+    ignores: ['.next/'],
+  },
 ]
 
 export default eslintConfig