Do not get the environment variables twice for same property(Environment variables not identified through properties file)

[deepthi912]

Issue:
The environment variable is not setting right with the "dynamic.env.config" property through controller.conf file.
Reference PR: #12307

Root cause:
Ideally the dynamic variables should be added once, but BaseControllerStarter & PinotServiceManager(startRole) are both trying to apply dynamic variables and this caused an issue when setting the environment variables from the dynamic.env.config properties through config file.

Fix:

• Added a Template flag variable to make sure that the env variables are not reloaded again after getting the value.
• Added a info log so as to see when the variable is being set from dynamic env configs.

Test Result:

Changed the port to "CONTROLLER_PORT" for the controller which is "9001" from the existing config 9000:

Before Change: throws error when launching controller

After change, running controller locally on "9001" :

[t0mpere]

If the config is applied twice then the function applyDynamicEnvConfig(List<Configuration> configurations, Map<String, String> environmentVariables) the second time gets ran will try to lookup env vars based on the values templated in the first call.
Using a templated=true|false property could prevent this when calling twice the constructor at L122 with the same configuration.

[deepthi912]

Yeah, it is going through already lookedup env variables again which resulted in the env variables not applied at all as second time, it will be null for that variable.

[Jackie-Jiang]

Seems we are not checking whether the property already exists. Is this expected? If so, let's modify the comments

[deepthi912]

Changed the description

[Jackie-Jiang]

Please take a look at the failed tests

[Jackie-Jiang]

Seems the failure is caused by #14237 and not related to this PR. Will take a look and get back

[Jackie-Jiang]

This PR is causing ControllerStarterStatelessTest to fail. Please take a look