Only delete envelopes when receiving HTTP status code 2xx

[philipphofmann]

Description

The HTTPTransport only checks if we receive any type of response from the server and then deletes the envelopes. Instead, it should only delete the envelope when receiving a 200, as Java does and as the develop docs recommend.

sentry-cocoa/Sources/Sentry/SentryHttpTransport.m

Lines 372 to 394 in 324f8b0

	[self.requestManager
	addRequest:request
	completionHandler:^(NSHTTPURLResponse *_Nullable response, NSError *_Nullable error) {
	if (weakSelf == nil) {
	SENTRY_LOG_DEBUG(@"WeakSelf is nil. Not doing anything.");
	return;
	}
	if (error && response.statusCode != 429) {
	SENTRY_LOG_DEBUG(@"Request error other than rate limit: %@", error);
	[weakSelf recordLostEventFor:envelope.items];
	}
	if (nil != response) {
	SENTRY_LOG_DEBUG(@"Envelope sent successfully!");
	[weakSelf.rateLimits update:response];
	[weakSelf deleteEnvelopeAndSendNext:envelopePath];
	} else {
	SENTRY_LOG_DEBUG(@"No internet connection.");
	[weakSelf finishedSending];
	}
	}];
	}

[kahest]

Note that we need to make sure we communicate possible impact well in release notes