Revert "[FLINK-29862] Upgrade to flink-shaded 16.0"

This reverts commit 9e1ff64.

There are some problems with the SSL setup.

docs/layouts/shortcodes/generated/rest_v1_dispatcher.html

@@ -1368,8 +1368,7 @@
  "job-accumulators" : {
  "type" : "array",
  "items" : {
- "type" : "object",
- "id" : "urn:jsonschema:org:apache:flink:runtime:rest:messages:JobAccumulatorsInfo:JobAccumulator"
+ "type" : "any"
  }
  },
  "serialized-user-task-accumulators" : {

docs/static/generated/rest_v1_dispatcher.yml

@@ -89,9 +89,11 @@ paths:
  $ref: '#/components/schemas/JarListInfo'
  /jars/upload:
  post:
- description: |-
- Uploads a jar to the cluster. The jar must be sent as multi-part data. Make sure that the "Content-Type" header is set to "application/x-java-archive", as some http libraries do not add the header by default.
- Using 'curl' you can upload a jar via 'curl -X POST -H "Expect:" -F "jarfile=@path/to/flink-job.jar" https://hostname:port/jars/upload'.
+ description: "Uploads a jar to the cluster. The jar must be sent as multi-part\
+ \ data. Make sure that the \"Content-Type\" header is set to \"application/x-java-archive\"\
+ , as some http libraries do not add the header by default.\nUsing 'curl' you\
+ \ can upload a jar via 'curl -X POST -H \"Expect:\" -F \"jarfile=@path/to/flink-job.jar\"\
+ \ https://hostname:port/jars/upload'."
  operationId: uploadJar
  requestBody:
  content: