Describe the bug

The following bug fixes have been applied to the community Spring Zeebe project after it was moved to the Spring SDK:

• fix: job worker stream disabled by default camunda-community-hub/spring-zeebe#813
• fix: VariableResolver can return null camunda-community-hub/spring-zeebe#771

Those bug fixes have not been applied to the Spring SDK and have led to user issues.

To Reproduce

• Using the @Variable annotation on a Job Worker, previous versions of spring-boot-starter-camunda-sdk (e.g. 8.5.5) would pass NULL if the variable did not exist. In 8.6.7 an exception is thrown and an Incident raised in Operate.
• Job streaming is enabled by default for job workers and can lead to 504 issues logged in the application if it's not configured correctly. Since it's not expected to be enabled by default, users are not aware that they need to configure it accordingly. Users can disable job streaming by default via configuration as a workaround.

Expected behavior

• Variables are passed as NULL if they don't exist.
• Job streaming is disabled by default for job workers.

Environment:

• OS:
• Zeebe Version: 8.6.x
• Configuration: