No, it does not mean your application was successful. Also it does not mean your application was refused. It means neither. It is simply an advisory that they have reached a decision and are letting you know that you will be contacted to collect your stuff from the VFS/VAC. It is a standard email sent out automatically by UKVI whenever they update the system.
They do not like to give out results via email because they see visa decisions as private beyond what email provides.
To find out if you were successful you should examine what you get back. If your passport has a bright shiny entry clearance, you were successful. If your passport has a refusal stamp along with a refusal notice, well… If you have been refused and you do not understand why, the odds are really good we have covered it in the site’s archives. See https://travel.stackexchange.com/questions/tagged/visa-refusal
In the email they say that they themselves don’t know the outcome of the assessment, so the answer to your question must be “no, it doesn’t mean either that you’ve been granted the visa or that you haven’t been granted the visa”.
Credit:stackoverflow.com‘