Update submodules: protobuf to v26.0 and abseil-cpp to 20240116.0 LTS

[yukawa]

Description

Protocol Buffers v26.0 is expected to be release soon, with most likely abseil-cpp LTS 20240116.0 as its official build configuration.

Let's update Mozc's submodules after Protocol Buffers v26.0 is released.

Version or commit-id

4efc54554b94e2f927a1c5f70e771351de6983ea

Environment

• OS: All

[yukawa]

Protocol Buffers v26.0 has been released.

• https://github.com/protocolbuffers/protobuf/releases/tag/v26.0

[yukawa]

Let's update submodules to the following commits.

• https://github.com/abseil/abseil-cpp/commit/4a2c63365eff8823a5221db86ef490e828306f9d
• https://github.com/protocolbuffers/protobuf/commit/d6511091a0cab1ad13f676a02676ad2a0e5eb9ae

[yukawa]

Completed with the following commits:

• https://github.com/google/mozc/commit/72671e68d5a79767de42b320d469d2fc6d869f6a
• https://github.com/google/mozc/commit/0df12d080dd063c6005d6f919308f67cadcf102e