Add null check to prevent potential runtime errors

[sigmoidr]

helpers.ts:

-    return !!provider.providers?.some(provider => checkProviderIdentity({ provider, device }));
+    return Array.isArray(provider.providers) && !!provider.providers.some(provider => checkProviderIdentity({ provider, device }));

wallets.ts:

-    checkProviderIdentity: ({ provider }) => !!provider && !!provider['ethereum'][ProviderIdentityFlag.Bitget],
+    checkProviderIdentity: ({ provider }) => !!provider && !!provider['ethereum'] && !!provider['ethereum'][ProviderIdentityFlag.Bitget]

[Adamj1232]

This null check looks good and passes testing