[BUGFIX] Invalid RSA key when submitting form twice

When submitting a RSA-supported form twice, the JS error
"Invalid RSA public key" is thrown. In order to suppress
this double RSA decryption, an additional JS check is needed.
The change also modifies the minified version of the JS
done with http://refresh-sf.com/yui/

Change-Id: I7133e320c76e14a6f6855f477ba5a34e50eecf58
Resolves: #40085
Releases: 6.1, 6.0, 4.7, 4.6, 4.5
Reviewed-on: https://review.typo3.org/17541
Reviewed-by: Dmitry Dulepov
Tested-by: Dmitry Dulepov
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel