bug: ion-searchbar width miscalculated on desktop when in scrollable zone

# Bug Report

**Ionic version:**

[x] **4.x**
[x] **5.x**

**Current behavior:**
When a `` is in a scrollable area and in desktop mode, the placeholder is truncated (by the clear button area I believe). The width of the searchbar doesn't seem to know that the scrollbar is here so the font size does not adjust.

**Expected behavior:**
The label shouldn't be truncated. On a phone it works fine.

**Steps to reproduce:**
Put a searchbar into a menu and then add many items to make it scrollable.

**Other information:**
Bug when scrollable :

No bug when not scrollable :

**Ionic info:**

```
Ionic:

Ionic CLI : 6.0.2 (C:\Users\xxx\AppData\Roaming\npm\node_modules\@ionic\cli)
Ionic Framework : @ionic/angular 5.0.1
@angular-devkit/build-angular : 0.801.3
@angular-devkit/schematics : 8.1.3
@angular/cli : 8.1.3
@ionic/angular-toolkit : 2.1.2

Capacitor:

Capacitor CLI : 1.4.0
@capacitor/core : 1.4.0

Utility:

cordova-res : not installed
native-run : not installed

System:

NodeJS : v12.13.1 (C:\Program Files\nodejs\node.exe)
npm : 6.12.1
OS : Windows 10

```