[Dynatrace][Mgmt] rename client name (#20742)

* Update readme.python.md

* Update readme.python.md

Co-authored-by: Yuchao Yan <yuchaoyan@microsoft.com>

Author: Wzb123456789

specification/dynatrace/resource-manager/readme.python.md

@@ -4,6 +4,7 @@ These settings apply only when `--python` is specified on the command line.
 Please also specify `--python-sdks-folder=<path to the root directory of your azure-sdk-for-python clone>`.
 
 ``` yaml $(python)
+title: DynatraceObservabilityMgmtClient
 azure-arm: true
 license-header: MICROSOFT_MIT_NO_VERSION
 package-name: azure-mgmt-dynatrace