`CallProcedure` request may not be routed to the best tablet when `partitionnum` > 1

**Bug Description**
When the `partitionnum` of a table is > 1, `CallProcedure` request is routed to a random tablet.

Current logic is:
`pid = rand_.Uniform(pid_num);`

The result is wrong but we may have to fetch data from remote tablet to the routed tablet.

**Expected Behavior**
`CallProcedure` request should be routed to the tablet based on the pk.

**Steps to Reproduce**

1. `SQLSDKQueryTest.RequestProcedureTest`: change create statement with `options(partitionnum=8)`
2. will generate a proxy task