Stat: Add Percent Change Option (#78250)

* Stat: Add Percent Change Option

* Ensure div style only applied for percent change

* Add metrics section to gdev

* Apply new style and fix nan truthy

* Handle no text case properly

* Only display percent change with value

* Improve styling

* Remove VizOrientation dep and improve styling

* Display percent change for text mode name

* Add check for undefined percentChange

* Don't show percent change option for all values

* Make metric alignment more robust

* Make percent change column case tighter

Check undefined directly to avoid truthy issues

* Simplify percentChange calculation

* Add documentation for show percent change

* Add tests for percent change

* Refactor big value and pull out percent change

* minor changes

* initial approach at addressing setting % change colors to be conventional (not super happy with handling of contrast)

* Clean up initial color change approach (no need to handle 0 case as is handled as NaN currently

* Update shadow styling and include icon

* Update docs/sources/panels-visualizations/visualizations/stat/index.md

Co-authored-by: Isabel <76437239+imatwawana@users.noreply.github.com>

* Stat: Add Percent Change Option (refactor and color exploration)  (#79504)

Co-authored-by: nmarrs <nathanielmarrs@gmail.com>

* some missed cleanup :D

* update percent change to show to not be tied to text value; update docs accordingly

* initial start for fixing scaling of % change for no text mode

* Fix styling for case where textmode is none

* Tweak styling a bit for icon and minimum padding

* Apply flex wrap to container styles

* Update gdev for stat panel tests

* attempt at fixing horizontal percent change styling / placement

---------

Co-authored-by: nmarrs <nathanielmarrs@gmail.com>
Co-authored-by: Isabel <76437239+imatwawana@users.noreply.github.com>
Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

docs/sources/panels-visualizations/visualizations/stat/index.md

@@ -122,6 +122,14 @@ Choose an alignment mode.
 - **Auto -** If only a single value is shown (no repeat), then the value is centered. If multiple series or rows are shown, then the value is left-aligned.
 - **Center -** Stat value is centered.
 
+### Show percent change
+
+Set whether percent change is displayed or not. Disabled by default.
+
+{{% admonition type="note" %}}
+This option is not applicable when the **Show** setting, under **Value options**, is set to **All values**.
+{{% /admonition %}}
+
 ## Text size
 
 Adjust the sizes of the gauge text.