Remove width rule for the "copy code" button

Setting a hard-coded width makes the button too small for
the label in many languages. Try it with Greek (el) and
Tamil (ta), for an extreme case.

If the width is not set explicitly, it is set automatically,
which should be just fine for this case, because this
button doesn't have to fit in with anything else.

Change-Id: I8921b373b59fd87d33f14a28d376be4eb2134b96
Merge "Remove width rule for the "copy code" button"