Add empty javadoc and sources jar for spring starters

[saragluna]

Description

#28967 enabled verification for build artifacts required by maven to publish in ci pipelines, which means the Spring ci will fail because the starters having no javadoc and sources jar. This PR will try to add these two jar files for starters.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

spring-cloud-azure-starter
spring-cloud-azure-starter-actuator
spring-cloud-azure-starter-appconfiguration
spring-cloud-azure-starter-cosmos
spring-cloud-azure-starter-data-cosmos
spring-cloud-azure-starter-eventhubs
spring-cloud-azure-starter-keyvault-certificates
spring-cloud-azure-starter-keyvault-secrets
spring-cloud-azure-starter-servicebus
spring-cloud-azure-starter-servicebus-jms
spring-cloud-azure-starter-storage-blob
spring-cloud-azure-starter-storage-file-share
spring-cloud-azure-starter-storage-queue
spring-cloud-azure-starter-integration-eventhubs
spring-cloud-azure-starter-integration-servicebus
spring-cloud-azure-starter-integration-storage-queue
spring-cloud-azure-starter-stream-eventhubs
spring-cloud-azure-starter-stream-servicebus
spring-cloud-azure-starter-active-directory
spring-cloud-azure-starter-active-directory-b2c

[JimSuplizio]

@saragluna I'm fine with the change however, I would like the <!-- START: Empty Java Doc --> and <!-- END: Empty Java Doc --> tags at the beginning and ends of the block like all of the other files have in them.