It is best to always escape the complete value of an attribute, not a partial value, as otherwise the escaping could be (partially) undone when the values are joined together.
While the hardcoded hyphen in this case don't necessarily create that risk, it may change to a value which could be problematic, so making it a habit to escape the value in one go is best practice.
Escaping the complete value also means that a single `esc_attr()` call can be used instead of two.
Follow-up to [14444], [16652], [55616], [56632].
See #58831.
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