Refactor asset_utils getAssetInfo lambda

The getAssetInfo function contained an inline lambda that triggered
the long-lambda ast-grep rule, requiring an inline suppression
(// ast-grep-ignore: long-lambda).

This commit extracts the lambda into a separate afterGetAssetInfo
function and uses std::bind_front to handle the asynchronous
callback. This aligns the code with the preferred bmcweb pattern for
D-Bus callbacks, improves readability, and allows the removal of the
static analysis suppression.

Tested:
- No other functional change.
- Tested on an AST2600 SoC platform.
- Redfish Service Validator passed with no new errors or warnings
introduced.

Change-Id: I471ab2402be00c81e629e965994a650024e120c4
Signed-off-by: Yuvakumar Selvamani <yuvakumars@ami.com>