Spike Curtis cee6b1ebde fix: wait for prompt on rich param CLI test (#15406)
Fixes a race in TestUpdateValidateRichParameters where the parameter is sent prior to the prompt.

Causes errors like: https://github.com/coder/coder/actions/runs/11681622439/job/32527173007

```
    ptytest.go:132: 2024-11-05 10:02:18.819: cmd: "bool_parameter"
    ptytest.go:167: 2024-11-05 10:02:18.819: cmd: matched "bool_parameter" = "bool_parameter"
    update_test.go:440: 2024-11-05 10:02:18.819: cmd: stdin: "cat\r\n"
    ptytest.go:132: 2024-11-05 10:02:18.819: cmd: "> Enter a value (default: \"\"): can't validate build parameter \"bool_parameter\": boolean value can be either \"true\" or \"false\""
    ptytest.go:167: 2024-11-05 10:02:18.819: cmd: matched "boolean value can be either" = "\n> Enter a value (default: \"\"): can't validate build parameter \"bool_parameter\": boolean value can be either"
    update_test.go:440: 2024-11-05 10:02:18.819: cmd: stdin: "\r\n"
    ptytest.go:167: 2024-11-05 10:02:18.819: cmd: matched "Enter a value" = " \"true\" or \"false\"\n> Enter a value"
    update_test.go:440: 2024-11-05 10:02:18.819: cmd: stdin: "false\r\n"
    ptytest.go:132: 2024-11-05 10:02:18.821: cmd: "> Enter a value (default: \"\"): can't validate build parameter \"bool_parameter\": boolean value can be either \"true\" or \"false\""
```
2024-11-07 16:47:15 +04:00
..