kapp reads confirmation prompt from stdin not tty

**What steps did you take:**

simplified example (real case uses a json input not `jq --null-input`):

```bash
#!/bin/bash -e -u -o pipefail
jq -r --null-input '["app1","app2"]|.[]' | while read -r app; do
kapp deploy -a "$app" -f "manifests/$app.yaml"
done
```

**What happened:**

```
Op: ...
Wait to: ...

Continue? [yN]: app1
invalid input (not y, n, yes, or no)
Continue? [yN]: app2
invalid input (not y, n, yes, or no)
```

**What did you expect:**

`kapp` to prompt for confirmation and read input from the tty since `--yes` was not passed.

**Anything else you would like to add:**

The bug here is that `kapp` tries to read interactive confirmation from stdin. That's rarely correct; the user may

```bash
kustomize build foo | kapp deploy -f -`
```

for example. But within the `while` loop, stdin points to the output of the `jq` command. `kapp` wasn't given `-f -` or anything so it isn't expected to read from stdin.

It should do what `sudo` and other tools do - detect an interactive tty and read directly from the tty, rather than stdin.

**Workaround**

To work around the bug, dup the stdin fd before you enter the loop or pass the pipe, e.g.

```bash
#!/bin/bash -e -u -o pipefail
# save stdin fd, so we can tell kapp to use it for prompting
exec 3<&0
jq -r --null-input '["app1","app2"]|.[]' | while read -r app; do
# pass kapp the original stdin
kapp deploy -a "$app" -f "manifests/$app.yaml" <&3
done
```

or

```bash
#!/bin/bash -e -u -o pipefail
exec 3<&0
kustomize build foo | kapp deploy -a myapp -f -
```

**Environment:**

- `kapp version 0.63.2`
- Ubuntu 24.04 LTS
- Kubernetes Server Version: v1.29.2

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