Alternative Improve _uploadReadByte (#2656)

* add opportunity for more than one retry to _uploadReadByte

* an alternative timeout-based method to making _uploadReadByte more resilient

* move timing variables in the correct scope

* implement and use client.getTimeout instead of hard-coded timeout in _uploadReadByte

* add missing return

* some refactoring to address respecting the timeout in a potentially deadlocked connection

* fix spelling in comment

* address review comments; move impl to cpp file for getTimeout, and remove local variable for currentMillis

* remove redundant cast

* need to check for timeout outside the inner while as well

* update WebUpdate example to print something in unexpected callback condition

* update log_e messages per review comments

cores/esp32/Stream.h

@@ -59,7 +59,7 @@ public:
 // parsing methods
 
     void setTimeout(unsigned long timeout);  // sets maximum milliseconds to wait for stream data, default is 1 second
-
+    unsigned long getTimeout(void);
     bool find(const char *target);   // reads data from the stream until the target string is found
     bool find(uint8_t *target)
     {