Revert "add applicant_id in GET /workflow_runs"

[dvacca-onfido]

Reverts #136

Reverting this change for now as it's causing a breaking change on in java client library, i.e.:

-    public List<WorkflowRun> listWorkflowRuns(Integer page, String status, OffsetDateTime createdAtGt, OffsetDateTime createdAtLt, String sort) throws ApiException {
-        ApiResponse<List<WorkflowRun>> localVarResp = listWorkflowRunsWithHttpInfo(page, status, createdAtGt, createdAtLt, sort);
+    public List<WorkflowRun> listWorkflowRuns(Integer page, String status, OffsetDateTime createdAtGt, OffsetDateTime createdAtLt, String 
sort, UUID applicantId) throws ApiException {
+        ApiResponse<List<WorkflowRun>> localVarResp = listWorkflowRunsWithHttpInfo(page, status, createdAtGt, createdAtLt, sort, applicantId);

A new PR will be submitted just after.