libsnapshot: remove temporary solution

Remove temporary estimation solution (using 4k to overestimate the cow).
With the updated estimation logic, we should be able to accurately
estimate the cow size with variable block sized compression

Bug: 322279333
Test: th
Change-Id: I199970048605a8d21d3791614ad88ca61662e1a3

fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp

@@ -214,15 +214,6 @@ bool CowWriterV3::Initialize(std::optional<uint64_t> label) {
             return false;
         }
     }
-
-    // TODO: b/322279333
-    // Set compression factor to 4k during estimation.
-    // Once COW estimator is ready to support variable
-    // block size, this check has to be removed.
-    if (IsEstimating()) {
-        header_.max_compression_size = header_.block_size;
-    }
-
     return true;
 }