fix(ios): explicitly invalidate session after completion

[janvennemann]

JIRA: https://jira.appcelerator.org/browse/TIMOB-26811

According to the docs for the delegate property, it holds a strong reference to the object. This creates a retain circle since we set the delegate to the request itself so neither the session nor the request will be properly released, creating a memory leak.

[vijaysingh-axway]

@janvennemann Inside error section of this function should we add
[self.session finishTasksAndInvalidate]; ? Because it is returning if error happens and responseFinished is not called.

`- (void)URLSession:(nonnull NSURLSession *)session task:(nonnull NSURLSessionTask *)task didCompleteWithError:(nullable NSError *)error
{
if (error != NULL) {
DebugLog(@"%s", PRETTY_FUNCTION);
self.response.readyState = APSHTTPResponseStateDone;
[self invokeCallbackWithState:APSHTTPCallbackStateReadyState];

self.response.connected = NO;
self.response.error = error;
[self invokeCallbackWithState:APSHTTPCallbackStateError];
[[self postForm] destroyTemporaryData];
return;

}
DebugLog(@"%s", PRETTY_FUNCTION);
self.response.downloadProgress = 1.f;
self.response.uploadProgress = 1.f;
self.response.readyState = APSHTTPResponseStateDone;
self.response.connected = NO;

[self responseFinished];
}`

[vijaysingh-axway]

Please fix the issue as mentioned in comment.

[janvennemann]

@vijaysingh-axway added invalidation to the error handler too!

[vijaysingh-axway]

CR passed.

[vijaysingh-axway]

@janvennemann Please update the library in SDK. Thanks!

[tristankenney]

Is this included in a preview build?

[janvennemann]

@tristankenney Unfortunately, this didn't make it into 8.0.0. It will be included in 8.0.1.