Trivial no-op fixup.
This was pointed out by #31053, which causes the include order to be shuffled around:
0[21:49:26.130] /ci_container_base/src/validationinterface.cpp:22:13: error: redundant 'RemovalReasonToString' declaration [readability-redundant-declaration,-warnings-as-errors]
1[21:49:26.130] 22 | std::string RemovalReasonToString(const MemPoolRemovalReason& r) noexcept;
2[21:49:26.130] | ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3[21:49:26.130] /ci_container_base/src/kernel/mempool_removal_reason.h:22:13: note: previously declared here
4[21:49:26.130] 22 | std::string RemovalReasonToString(const MemPoolRemovalReason& r) noexcept;
5[21:49:26.130] | ^
I don’t see any reason why the include shouldn’t just be used.