Fix a lambda capture problem in TextDumpsysSection

The [&] capture does not handle smart pointers (unique_ptr, unique_fd
etc) well, which lead to leaked pointers. Fix by explicitly move the
smart pointers.

Bug: 158097879
Test: Build, flash and take an incident report. Verify no crash
Change-Id: I5150aa3dddf9d59c1c9d6d32370370e8cde23946