chunked_vector_test fails to compile with recent boost versions

[lkshminarayanan]

When compiled with boost version 1.82+, chunked_vector_test fails with the following error :

/Scylla/scylladb/test/boost/chunked_vector_test.cc:378:24: error: no member named 'optional' in namespace 'std'
    auto filler = std::optional<exception_safe_class>(checker);
                  ~~~~~^
/Scylla/scylladb/test/boost/chunked_vector_test.cc:378:33: error: 'exception_safe_class' does not refer to a value
    auto filler = std::optional<exception_safe_class>(checker);
                                ^
/Scylla/scylladb/test/boost/chunked_vector_test.cc:139:7: note: declared here
class exception_safe_class {
      ^
2 errors generated.
ninja: build stopped: subcommand failed.

This does compiles with older versions of boost. Although the code is unrelated to boost, the optional library seems to get implicitly included in older versions and not in the newer versions causing this issue. I have verified this by generating the dependency graph with version 78, which has the optional header in the list vs the graph with version 83, which doesn't have that header in the list.

[lkshminarayanan]

Note that this is a followup to 4bbb66f, so it needs to be backported to older versions.

[lkshminarayanan]

Fixed by #18739