Adding not null Assertion for IntentAssert

During development of a deep linking feature for a client I ran into an issue where android-fest assertion was throwing a NullPointerException. This happens when you check for the component name in an IntentAssert but for some reason the ComponentName was not set (for whatever reason). This change adds a null check for component assertion as sometimes component can be null. 

Just an FYI - Since this repo is now gradle based, the Contributing markdown file seems to be out of date as it specifies `mvn clean verify` prior to pull request submission. :smile: