Avoid expensive set construction in Config constructor

[fractalwrench]

Goal

Initializing Configuration was taking more time than it needed to due to the construction of some unnecessary sets. The toSet() implementation in Kotlin seems like it can be particularly slow in some circumstances, as it constructs a LinkedHashSet. This is unnecessary for the purposes of Configuration.

Changeset

• Avoided creation of unnecessary field for redactedKeys
• Initialized plugins with a HashSet rather than a LinkedHashSet
• Set enabledBreadcrumbTypes to null rather than constructing a set - this has the same behaviour as setting all the values

Without these optimizations Configuration took ~38ms to initialize, whereas with them it took ~9ms. It's worth noting that this only seems to be on a cold start, suggesting that there is some one-off work required when the JVM is initialized. Therefore the differences don't show up in the automated benchmarks and have been manually profiled instead.

Testing

Relied on existing test coverage.

[bugsnagbot]

Android notifier sizes

Format	Size impact of Bugsnag (kB)	Size impact of Bugsnag when Minified (kB)
APK	1511.91	1408.8
arm64_v8a	402.11	295.61
armeabi	385.72	279.22
armeabi_v7a	365.25	262.85
x86	443.05	336.55
x86_64	422.58	320.18

Generated by 🚫 Danger

[lemnik]

LGTM