NEXUS-909 feat Enable custom server URLs in the workflow endpoints

[yuming-long]

Summary

• server_url logic in workflow endpoints is now the same as partition endpoint: user should be able to pass it from Client init to each endpoint and if no input we will just fallback to default based on endpoint operation
• NOTE changes to developers: generate GHA will need manual changes
  • you need to change the automate speakeasy bot PR made generate GHA -> so that it won't revert the changes on base_url in each endpoint (see chore: 🐝 Update SDK - Generate 0.34.0 #266)
  • we could add those file under .genignore so that speakeasy bot ignore the ^^ changes -> but i don't like this way since we might still need to modify workflow API endpoint and speakeasy bot will ignore them if we do
  • another trick i found that could solve the issue -> we could pay speakeasy more... but still not very flexible
  • or we could also patch _get_url in basesdk.py but thats in deeper stack of code might be difficult to read the flow (and write tests)
  • all reasons ^^^^ include i decide to go with manual changes in generate GHA -> we need a developer to approve that auto PR anyway

Test

you got three ways of using the url

## make sure the version of unstructured_client is the local one should be 0.34.0
import unstructured_client
from unstructured_client.models import operations, shared
from unstructured_client import UnstructuredClient
# 1. init custom url when you create the Client (suggested way for in-VPC)
uc_client = UnstructuredClient(server_url="http://localhost:8081/", api_key_auth="XXXX")

create_workflow_data = {
    "name": "custom sdk workflow",
    "workflow_type": shared.WorkflowType.BASIC,
}

client_res = uc_client.workflows.create_workflow(request={
    "create_workflow": create_workflow_data,
})
# 2. pass url when you call the specific endpoint (probably nobody will use this one...)
uc_client = UnstructuredClient(api_key_auth="XXX")

create_workflow_data = {
    "name": "custom sdk workflow",
    "workflow_type": shared.WorkflowType.BASIC,
}

client_res = uc_client.workflows.create_workflow(
    request={"create_workflow": create_workflow_data,},
    server_url="http://localhost:8081/",
)
# 3. no passing any url, fallback to default
uc_client = UnstructuredClient(api_key_auth="XXX)

create_workflow_data = {
    "name": "custom sdk workflow",
    "workflow_type": shared.WorkflowType.BASIC,
}

client_res = uc_client.workflows.create_workflow(
    request={"create_workflow": create_workflow_data,},
)

and responses would be (last one is default fallback)

INFO: HTTP Request: POST http://localhost:8081/api/v1/workflows/ "HTTP/1.1 200 OK"
INFO: HTTP Request: POST http://localhost:8081/api/v1/workflows/ "HTTP/1.1 200 OK"
INFO: HTTP Request: POST https://platform.unstructuredapp.io/api/v1/workflows/ "HTTP/1.1 200 OK"