GUI crash on squish testing

Squish tests failing as unable to launch ibex client - client launched OK by hand, so issue only when client started via squish framework. Seems to have been happening since 27th May when GUI dependency update was merged https://github.com/ISISComputingGroup/ibex_gui/pull/1842

```
*2026-06-19 17:47:50.816 [Start Level: Equinox Container: 999586b2-e5e5-4837-ac89-a6a1bf1176fb] INFO uk.ac.stfc.isis.ibex.logger.IsisLog - Starting uk.ac.stfc.isis.ibex.logger
*2026-06-19 17:47:50.857 [Start Level: Equinox Container: 999586b2-e5e5-4837-ac89-a6a1bf1176fb] INFO uk.ac.stfc.isis.ibex.logger.IsisLog - java.util.logging.Logger logger global hooked successfully (message from log4j).
*2026-06-19 17:47:50.857 [Start Level: Equinox Container: 999586b2-e5e5-4837-ac89-a6a1bf1176fb] INFO uk.ac.stfc.isis.ibex.logger.IsisLog - java.util.logging.Logger logger global hooked successfully (message from java logger).
*2026-06-19 17:47:51.139 [main] INFO uk.ac.stfc.isis.ibex.epics.pvmanager.PVManagerSettings - Setting diirt.home env var to %s/C:/Instrument/Apps/Client_E4/plugins/uk.ac.stfc.isis.ibex.epics_1.0.0.6562/diirt/
*2026-06-19 17:47:51.213 [main] ERROR org.eclipse.osgi - StackMapTable error: bad offset
Exception Details:
Location:
org/eclipse/swt/widgets/Display.readAndDispatch()Z @0: aload_0
Reason:
Invalid stackmap specification.
Current Frame:
bci: @68
flags: { }
locals: { 'org/eclipse/swt/widgets/Display' }
stack: { }
Bytecode:
0000000: 2ab6 0274 01b3 0157 2ab6 0950 2ab6 0952
0000010: 572a b609 5557 2ab6 0958 572a b401 e809
0000020: 0303 04b8 0878 9900 4a2a 2ab4 01e8 b404
0000030: 932a b401 e8b4 0490 2ab4 01e8 b406 b62a
0000040: b401 e8b4 0bb3 b80b b799 0005 04ac 2a2a
0000050: b401 e8b6 0876 9a00 132a b401 e8b8 0458
0000060: 572a b401 e8b8 045c 582a b609 5b57 04ac
0000070: 2ab6 02b3 9a00 0d2a 03b6 0864 9a00 0503
0000080: ac04 ac
Stackmap Table:
same_frame_extended(@68)
same_frame(@75)
same_frame(@92)

org.eclipse.ui.internal.Workbench.createDisplay(Workbench.java:766)
org.eclipse.ui.PlatformUI.createDisplay(PlatformUI.java:185)
uk.ac.stfc.isis.ibex.e4.product.Application.start(Application.java:63)
org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:219)
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:149)
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:115)
org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:467)
org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:298)
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
java.base/java.lang.reflect.Method.invoke(Method.java:565)
org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:615)
org.eclipse.equinox.launcher.Main.basicRun(Main.java:563)
org.eclipse.equinox.launcher.Main.run(Main.java:1415)
```

Inizia esaminando la PR 1842 di aggiornamento delle dipendenze GUI e il percorso di avvio di Squish, quindi analizza l’errore in org.eclipse.swt.widgets.Display.readAndDispatch e le chiamate attraverso PlatformUI.createDisplay e Application.start. Riproduci l’avvio del client tramite Squish e confrontalo con un avvio manuale; il lavoro è completato quando il test Squish avvia il client senza il crash di stackmap.

Scritto dal modello di indicizzazione a partire dal testo della issue.