[Enhancement](compaction) empty string optimize for binary dict code

[BiteTheDDDDt]

Proposed changes

before:
- 5.85% doris::segment_v2::BinaryDictPageBuilder::add                                                                                                                            ▒
    + 2.26% phmap::priv::raw_hash_set<phmap::priv::FlatHashMapPolicy<doris::Slice, unsigned int>, doris::segment_v2::BinaryDictPageBuilder::HashOfSlice, phmap::EqualTo<doris::Sli▒
    + 0.70% doris::segment_v2::BinaryPlainPageBuilder<(doris::FieldType)17>::add                                                                                                  ▒
+ 1.41% doris::segment_v2::TypedZoneMapIndexWriter<(doris::PrimitiveType)23>::add_values



after:
- 4.91% doris::segment_v2::BinaryDictPageBuilder::add                                                                                                                            ▒
    + 1.06% doris::segment_v2::BinaryPlainPageBuilder<(doris::FieldType)17>::add                                                                                                  ▒
        1.00% phmap::priv::raw_hash_set<phmap::priv::FlatHashMapPolicy<doris::Slice, unsigned int>, doris::segment_v2::BinaryDictPageBuilder::HashOfSlice, phmap::EqualTo<doris::Sli▒
        0.73% doris::segment_v2::BinaryDictPageBuilder::is_page_full                                                                                                                ▒
+ 0.60% doris::segment_v2::TypedZoneMapIndexWriter<(doris::PrimitiveType)23>::add_values

Problem summary

Describe your changes.

Checklist(Required)

1. Does it affect the original behavior:
   • Yes
   • No
   • I don't know
2. Has unit tests been added:
   • Yes
   • No
   • No Need
3. Has document been added or modified:
   • Yes
   • No
   • No Need
4. Does it need to update dependencies:
   • Yes
   • No
5. Are there any changes that cannot be rolled back:
   • Yes (If Yes, please explain WHY)
   • No

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[zenoyang]

LGTM

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.