Automatically resize text areas (+ text fields that can be multi-line)

[nikku]

Is your feature request related to a problem? Please describe

As a user I'm often editing text that may be multi-line (or single line).

I#m struggling to use the properties panel as the text input controls don't work intuitive for me:

• Text areas are not sized by content but instead fixed to three lines. This is too much for no content, but not enough for any reasonable amount of text
• Text fields (i.e. Name) can sometimes be multi-line. I'd expect them to be single line per default but expand sensibly on multi-line inputs.

Describe the solution you'd like

Support for automatic resizing:

• Single line text fields can resize to multi-line fields
• Text areas can resize (expand) up to a maximum size
• Intially text area and single line fields render based on the content (up to a certain constraint).

Describe alternatives you've considered

None.

Additional context

I believe we did have a better UX around multi-line fields in bpmn-js-properties-panel@0.x.

Related to bpmn-io/properties-panel#25

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The following shows my usual flow of "editing" multi-line text: