fix: rename DisableSentryNative to SentryNative

[Flash0ver]

follow-up to #4107

• Rename unreleased MSBuild property from DisableSentryNative to SentryNative
  • to keep all Sentry-related MSBuild properties prefixed with Sentry..
• Change the value to opt-out from true to false|disable
  • similar to SentryImplicitUsings, also an opt-out
  • opposite to ImplicitUsings, which is an opt-in
• Keep disabling native libraries as explicit opt-out

[jamescrosswell]

Suggested change

	// This way, `Sentry.Native.IsEnabled` should be treated as a compile-time constant for trimmed apps.
	// This way, `SentryNative.IsEnabled` should be treated as a compile-time constant for trimmed apps.

It's internal static class SentryNative

[Flash0ver]

ah ... it's referring to the property name, not the switch name ... my bad ... reverted

[jamescrosswell]

LGTM