test/objectstore/..ops_replayer: cleanup include std::format

test/objectstore/..ops_replayer: cleanup include std::format

clang16 hides std::format behind `-fexperimental-library` [1].
This is no longer the case with clang 17 [2].
As std::fmt is not used in this file we can clean it up for now.

Note: Future commits will aim to switch to clang17.

[1] https://prereleases.llvm.org/16.0.0/rc3/projects/libcxx/docs/UsingLibcxx.html#extensions-to-format
[2] https://releases.llvm.org/17.0.1/projects/libcxx/docs/ReleaseNotes/17.html

Signed-off-by: Matan Breizman <mbreizma@redhat.com>