The ViewEngine translation extractor does not convert `-` to `_` for
placeholders that represent custom elements. For example `<app-component>`
gets converted to placeholders like `START_TAG_APP-COMPONENT`.
In `$localize` placeholders are expected to be snake-case, not kebab-case.
So we must normalize them when parsing a translation file that might have
been created via the View Engine translation extractor.
The `$localize` extraction code will normalize these placeholders when
creating translation files in the first place.
Fixes#34151
PR Close#34155
d529b55651