[FEATURE] 'floorplan.text_set' should support element which has text as child

[Skarbo]

Description
Prior to version 1.0.36 setText would look for any existing tspan children and change the child text.

From version 1.0.36 with new line feature setText will presume that entity is a text node and append tspan with the text to that node.

This does not work if you use floorplan.text_set on a entity that is a g node, for example.

Current experience
Original SVG

<svg>
<g id="temperature.kitchen">
<text><tspan x="5" y="5">99.9°</tspan></text>
</g>
</svg>

YAML

- name: Temperatures
   entities:
     - element: temperature.kitchen
       entity: sensor.kitchen
   state_action:
     - service: floorplan.text_set
       service_data: '10.0°'

Produced SVG

<svg>
<g id="temperature.kitchen">
<tspan>10.0°</tspan>
</g>
</svg>

Expected SVG

<svg>
<g id="temperature.kitchen">
<text><tspan x="5" y="5">10.0°</tspan></text>
</g>
</svg>

Suggestion
Update setText to look for child text node if element is not SVGTextElement.

static setText(
  textElement: HTMLElement | SVGElement,
  text: string,
  shiftAxisY: string
): void {
  if (!(textElement instanceof SVGTextElement)) {
    textElement = textElement.querySelector('text') || textElement;
  }

[bernji]

I sencond that as I have the same problem: attribes of child (e.g. tsdpan) of text nodes are erased

[exetico]

That's a fair input. I'll fix it whenever possible. I thought @pkozul looked into it.

PR's also much appreciated, if they're tested. Else,I'll try and prioritize it as soon as possible.

[exetico]

Before fix:

<svg height="100%" width="100%" xmlns:xlink="http://www.w3.org/1999/xlink" style="height: 100%; width: 100%; margin: auto; cursor: default; opacity: 1; display: block;">
<g id="temperature.kitchen"><tspan>21.42</tspan></g>
</svg>

After fix:

<svg height="100%" width="100%" xmlns:xlink="http://www.w3.org/1999/xlink" style="height: 100%; width: 100%; margin: auto; cursor: default; opacity: 1; display: block;">
<g id="temperature.kitchen" class="floorplan-hover" style="cursor: pointer;">
<text><tspan x="5" y="5">21.42</tspan></text>
<title>...(removed)...</title></g>
</svg>

Branch: https://github.com/ExperienceLovelace/ha-floorplan/tree/bug/text_set_use_existing_tspan

I have also added the logics to save the x and y, if it's a single tspan. I don't know why I didn't think of that while implementing the other feature.

[exetico]

Kindly check with: https://github.com/ExperienceLovelace/ha-floorplan/blob/dev/dist/floorplan.js

It's currently in the dev-branch.