Upgrade FlatBuffers from 24.3.25 to 25.2.10

[afarber]

Fix the #7235 by

• Append FlatBuffers specific commands to scripts/update_dependencies.sh
• Upgrade FlatBuffers by running git subtree pull to preserve the upstream git log
• Upgrade Flatbuffer npm version in package.json
• Update obsolete link in scripts/update_dependencies.sh comment
• Ignore .gradle folder

Tasklist

• CHANGELOG.md entry (How to write a changelog entry)
• update relevant Wiki pages
• add tests (see testing documentation)
• review
• adjust for comments

Requirements / Relations

Link any requirements here. Other pull requests this PR is based on?

[afarber]

I need to improve this PR:

• The git subtree was not cleanly exexuted
• New Flatbuffers dropped Javascript support, but we need the features/support/fbresult_generated.js