[Java] Update samples notes to indicate that the media driver should be launched first.
[Java] Update samples notes to indicate that the media driver should be launched first.

mikeb01/Aeron,mikeb01/Aeron,galderz/Aeron,mikeb01/Aeron,galderz/Aeron,real-logic/Aeron,real-logic/Aeron,EvilMcJerkface/Aeron,EvilMcJerkface/Aeron,mikeb01/Aeron,EvilMcJerkface/Aeron,galderz/Aeron,EvilMcJerkface/Aeron,real-logic/Aeron,galderz/Aeron,real-logic/Aeron