O3-5254: Exclude jackson-dataformat-yaml to prevent bundling Jackson dataformat (#689)
* O3-5254: Exclude jackson-dataformat-yaml to prevent bundling Jackson
The webservices.rest-omod-common module was packaging
`jackson-dataformat-yaml` via swagger-core, which resulted in Jackson
artifacts being included in the OMOD. This contributed to classloader
conflicts during OpenMRS startup (LinkageError: ObjectReader), especially
when demo data generation is enabled.
By excluding jackson-dataformat-yaml, the module now defers to the
Jackson version provided by the platform/container, preventing duplicate
Jackson classes from being shipped inside the OMOD.
* jackson-dataformat-yaml as a test-scoped dependency
