clickButton(String) is overly permissive in finding buttons

[jtnord]

#2592 was prompted as the text matching on clickButton was overly permissive, looking for contains rather than being equal.

If a button contains an SVG with text then that text should be included in the match, ie if the button is defined as follows:

<button>this is a button
  <svg viewBox="0 0 240 80" xmlns="http://www.w3.org/2000/svg">
    <text x="20" y="35" class="small">My</text>
    <text x="40" y="35" class="heavy">cat</text>
    <text x="55" y="55" class="small">is</text>
    <text x="65" y="55" class="Rrrrr">Grumpy!</text>
  </svg>  
</button>

then clickButton() should be called as clickButton("this is a button\nMy\ncat\nis\nGrumpy"); not clickButton("this is a button");

This causes issues when in the example of the referenced PR there are other buttons that contain "Run" that are matched.

TL;DR ByFactory.byButton with String should take exact text to match, or an ID. it should not use partial text.