Cherry-pick #18890 to 7.x: Add check on <no value> config option value for the azure input resource_manager_endpoint

CHANGELOG.next.asciidoc

@@ -56,6 +56,7 @@ happened. {issue}13920[13920] {pull}18223[18223]
 - With the default configuration the cef and panw modules will no longer send the `host`
 field. You can revert this change by configuring tags for the module and omitting
 `forwarded` from the list. {issue}13920[13920] {pull}18223[18223]
+- Adds check on `<no value>` config option value for the azure input `resource_manager_endpoint`. {pull}18890[18890]
 - Okta module now requires objects instead of JSON strings for the `http_headers`, `http_request_body`, `pagination`, `rate_limit`, and `ssl` variables. {pull}18953[18953]
 - Adds oauth support for httpjson input. {issue}18415[18415] {pull}18892[18892]
 

x-pack/filebeat/input/azureeventhub/eph.go

@@ -89,7 +89,7 @@ func (a *azureInput) runWithEPH() error {
 
 func getAzureEnvironment(overrideResManager string) (azure.Environment, error) {
 	// if no overrride is set then the azure public cloud is used
-	if overrideResManager == "" {
+	if overrideResManager == "" || overrideResManager == "<no value>" {
 		return azure.PublicCloud, nil
 	}
 	if env, ok := environments[overrideResManager]; ok {

x-pack/filebeat/input/azureeventhub/eph_test.go

@@ -41,4 +41,8 @@ func TestGetAzureEnvironment(t *testing.T) {
 	resMan = "http://management.invalidhybrid.com/"
 	env, err = getAzureEnvironment(resMan)
 	assert.Errorf(t, err, "invalid character 'F' looking for beginning of value")
+	resMan = "<no value>"
+	env, err = getAzureEnvironment(resMan)
+	assert.NoError(t, err)
+	assert.Equal(t, env, azure.PublicCloud)
 }