Git submodule: Bump libs/hbb_common from 49c6b24 to 7cf11f7 (#523)

Bumps [libs/hbb_common](https://github.com/rustdesk/hbb_common) from `49c6b24` to `7cf11f7`.
- [Commits](rustdesk/hbb_common@49c6b24...7cf11f7)

---
updated-dependencies:
- dependency-name: libs/hbb_common
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]