fix(ui5-input): correct acc info implementation

[ivoplashkov]

The _accInfo method used to return undefined for aria attributes. Now the method works as expected.

[CLAassistant]

All committers have signed the CLA.

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}