Rename ScheduledTasksObservabilityAutoConfiguration to ScheduledTasksObservationAutoConfiguration

[wilkinsona]

We have several auto-configuration classes named …ObservationAutoConfiguration:

• BatchObservationAutoConfiguration
• GraphQlObservationAutoConfiguration
• R2DBCObservationAutoConfiguration
• RestClientObservationAutoConfiguration
• RestTemplateObservationAutoConfiguration
• WebClientObservationAutoConfiguration
• WebFluxObservationAutoConfiguration
• WebMvcObservationAutoConfiguration

But only one named …ObservabilityAutoConfiguration:

• ScheduledTasksObservabilityAutoConfiguration

It should be renamed to align with the others.

[wilkinsona]

Closing in favor of #46995. Thanks for the PR, @maziyarbahramian.