Fixed a bug in the AttrBuilder related experimental C APIs, where the string

value `attr_name` passed into `TF_AttrBuilderSetType()` could get destroyed
before a subsequent call to `TF_AttrBuilderCheckCanRunOnDevice()` on the same
`builder`.

That is a use-after-free error, since `builder` stores a string_view version of
`attr_name`, and uses it in the latter API call.

PiperOrigin-RevId: 223425447