See also #30651
Append operator of `std::filesystem::path` will replace whole path when
the param of "/" operation is an absolute path.
In "All-in-one" mode, this shall cause ChunkCache removing the original
vector data file when building chunk cache during/after load procedure.
This PR changes the ChunkCache path generation logic to a separate
function in which will check whether the file path is absolute or not.
If the file path is absolute, it removes the root path prefix and return
concatenated file path.
---------
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
18c351efa6