templatizeExtraLabels doesn't stringify typically non-string values

Describe the bug

apollographql.templatizeExtraLabels does not properly translate string values to strings when creating labels if they would otherwise be another scalar type.

For example, adding:

router:
    extraLabels:
        somelabel: "true"

would end up attempting to create this label:

somelabel: true

which would cause an error.

To Reproduce

Steps to reproduce the behavior:

1. Create an extraLabels label that has a string value that would otherwise be a non-string value (like "true")
2. Observe manifest creation failing with an error around labels saying something like contains non-string key in the map: true is of the type bool, expected string

Expected behavior

Manifest generation would work just fine.

Additional context

Overriding apollographql.templatizeExtraLabels with the following that uses toJson to stringify the label value solved the issue, but it could introduce breaking changes:

{{- define "apollographql.templatizeExtraLabels" -}}
{{- range $key, $value := .Values.extraLabels }}
{{ printf "%s: %s" $key (toJson (include  "apollographql.tplvalues.render" ( dict "value" $value "context" $)))}}
{{- end -}}
{{- end -}}

Locate the apollographql.templatizeExtraLabels template and reproduce the failure with an extraLabels value such as somelabel: "true". The work is done when manifest generation succeeds and the resulting label value remains a string; the issue does not name a specific file or test to run.