Remove cosmos permissions properties and set default connection mode

[saragluna]

Per discussion with the architects:

cosmos.gateway-connection.proxy and spring.cloud.azure.cosmos.permissions are complex types, property is defined, but nested properties are not defined. there is no metadata and there is no way to populate them via config. They should not be listed as properties considering this.

This is not just a metadata concern, users are not able to configure corresponding SDK options type in application.yml.
There should be some tests that validate how each configuration is applied if it's exposed at all. Suggestion is to remove 'permissions' property until it can be supported and tested

cosmos.connection-mode is null by default, meaning this code block does nothing and gateway or direct configs are ignored. it should follow SDK default (direct) or clearly communicate in docs that property is required (and log error if it's not provided)

#27112

[moarychan]

The test properties should be removed in sync,

azure-sdk-for-java/sdk/spring/spring-cloud-azure-service/src/test/java/com/azure/spring/service/implementation/cosmos/TestAzureCosmosHttpProperties.java

Line 41 in c8a7610

private final List<CosmosPermissionProperties> permissions = new ArrayList<>();

[saragluna]

cool, thanks

[saragluna]

Will do in another PR.

[moarychan]

The test properties should be updated in sync, com.azure.spring.service.implementation.cosmos.TestAzureCosmosHttpProperties#connectionMode

[backwind1233]

LGTM