[FIX] format: dispatch only once

Steps to reproduce:
- select a huge zone with numbers
- click on the "Increase decimal places" tool in the top bar

=> there's one dipatched command for each position in the zone, which
can huge.

We want:
- one dispatched command per format
- positions grouped to a single zone if there are contiguous (a single big
  zone instead of many zones, each being actually a single position)

Issue introduced by 1b66725

Task: 4091502

src/plugins/ui_feature/format.ts

@@ -2,14 +2,16 @@ import {
   changeDecimalPlaces,
   createDefaultFormat,
   isDateTimeFormat,
-  positions,
   positionToZone,
+  positions,
 } from "../../helpers";
+import { futureRecomputeZones } from "../../helpers/recompute_zones";
 import {
   CellPosition,
   CellValueType,
   Command,
   Format,
+  Position,
   SetDecimalStep,
   UID,
   Zone,
@@ -41,6 +43,7 @@ export class FormatPlugin extends UIPlugin {
    * evaluated and updated with the number type.
    */
   private setDecimal(sheetId: UID, zones: Zone[], step: SetDecimalStep) {
+    const positionsByFormat: Record<Format, Position[]> = {};
     // Find the each cell with a number value and get the format
     for (const zone of zones) {
       for (const position of positions(zone)) {
@@ -50,15 +53,22 @@ export class FormatPlugin extends UIPlugin {
           // of the format
           const locale = this.getters.getLocale();
           const newFormat = changeDecimalPlaces(numberFormat, step, locale);
-          // Apply the new format on the whole zone
-          this.dispatch("SET_FORMATTING", {
-            sheetId,
-            target: [positionToZone(position)],
-            format: newFormat,
-          });
+          positionsByFormat[newFormat] = positionsByFormat[newFormat] || [];
+          positionsByFormat[newFormat].push(position);
         }
       }
     }
+    // consolidate all positions with the same format in bigger zones
+    for (const newFormat in positionsByFormat) {
+      const zones = futureRecomputeZones(
+        positionsByFormat[newFormat].map((position) => positionToZone(position))
+      );
+      this.dispatch("SET_FORMATTING", {
+        sheetId,
+        format: newFormat,
+        target: zones,
+      });
+    }
   }
 
   /**