Remove example metadata for extension (#4785)

doc/extensions/myexampleextension/azext_myexampleextension/azext_metadata.json

@@ -1,3 +0,0 @@
-{
-    "azext.maxCliVersion": "2.0.12"
-}

doc/extensions/myexampleextension/setup.py

@@ -37,6 +37,5 @@ setup(
     url='https://github.com/ORG/REPO',
     classifiers=CLASSIFIERS,
     packages=find_packages(),
-    package_data={'azext_hello': ['azext_metadata.json']},
     install_requires=DEPENDENCIES
 )