Remove unnecessary error check

[Nigel2392]

While inspecting the Truncate function to gain some inspiration, I noticed it has an unnecessary error check.

This PR specifically targets the following blob:
https://github.com/gohugoio/hugo/blob/3aa22b09425ab9e4e4d79c328ae16692cb3df736/tpl/strings/truncate.go#L70C1-L76C3

if err != nil {
	return "", errors.New("text to truncate must be a string")
}
text, err := cast.ToStringE(textParam)
if err != nil {
	return "", errors.New("text must be a string")
}

The previous error might have belonged to an old piece of code, but as it stands - it will always be nil.

[CLAassistant]

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