Remove legacy crash reporting upload process (#7076)

Author: samedson

Crashlytics/CHANGELOG.md

@@ -1,3 +1,6 @@
+# Unreleased
+- [changed] Removed obsolete crash reporting mechanism from the SDK
+
 # v7.3.0
 - [added] Added Crashlytics support for x86 apps running on Apple Silicon via Rosetta 2
 - [changed] Decreased Crashlytics CocoaPods minimum deployment target from iOS 10 to iOS 9