regex_replace() captured string doesn't work

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#### Overview of the Issue

The reference to captured string in `regex_replace()` doesn't work as expected.

#### Reproduction Steps

From :

```
> regex_replace("-ab-axxb-", "a(x*)b", "${1}W")
-W-xxW-
```

My actual result:

```
$ packer console -config-type=hcl2
> regex_replace("-ab-axxb-", "a(x*)b", "${1}W")
> -1W-1W-
```

### Packer version

From `packer version`

Packer v1.8.7

### Simplified Packer Template

N/A.

### Operating system and Environment details

```
$ sw_vers
ProductName: macOS
ProductVersion: 13.4
BuildVersion: 22F66

$ uname -a
Darwin YNVWYNWVX4 22.5.0 Darwin Kernel Version 22.5.0: Mon Apr 24 20:52:24 PDT 2023; root:xnu-8796.121.2~5/RELEASE_ARM64_T6000 arm64
```

### Log Fragments and crash.log files

N/A.

Start by reproducing the discrepancy through the `regex_replace()` entry point in `packer console -config-type=hcl2`, using the example from the issue. Trace how the `${1}` replacement is interpreted and verify that the result preserves the captured strings as documented: `-W-xxW-`.

Written by the indexing model from the issue text.