Fixes to List Workflows Basic route handler

[adhityamamallan]

Summary

• Add extra validation to Zod schema to ensure that only one filter is set
• Explicitly pass filter type to GRPC endpoint
• Rewrite the endpoint logic a bit to fix type errors

Test plan

Ran locally as part of the overall Basic Visibility changes

[3vilhamster]

nit: This looks cool, but might be easier to make it more readable explicitly:

var params = ...
if queryParams.workflowId || queryParams.runId {
   params.filters = 'executionFilter'
   executionFilter: {
        workflowId: queryParams.workflowId,
        runId: queryParams.runId,
      },
}
if queryParams.workflowType {
   params.filters = 'typeFilter'
   typeFilter: {
        name: queryParams.workflowType,
      },
}

Though, this is what we usually do in Go. I'm unsure about JS style :)

[adhityamamallan]

I guess this would be more JS-y; I tend to avoid lets and vars if possible.