Update zulip checkout to 313f8caff7099b0991fc50cb116ae7145e459152

[MTtankkeo]

See the following PR for the reason behind this change:
zulip/zulip-flutter#1833

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[Piinks]

Can you check the merge conflict here? I am not sure if it is a later or earlier commit.

[MTtankkeo]

Can you check the merge conflict here? I am not sure if it is a later or earlier commit.

It seems that e9a7288da553d07d0a47cae1aa40d633254cfe2c is the more recent commit.