Increase the character limit for translations in taskbar pinning edu

The current character limit for the taskbar pinning edu subtitle does
not fit many translations. We are increasing the character limit to
enable proper translations.

Flag: ACONFIG com.android.launcher3.enable_taskbar_pinning TRUNKFOOD
Fix: 323943380
Test: N/A
Change-Id: I56225711c475e617451e5db0b1c226e3603e5c02