Increase broadcast channel sizes

[adzialocha]

Closes #245

📋 Checklist

• Add tests that cover your changes
• Add this PR to the Unreleased section in CHANGELOG.md
• Link this PR to any issues it closes
• New files contain a SPDX license header

[codecov]

Codecov Report

Merging #257 (1cc4b1c) into main (0bf77f5) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #257   +/-   ##
=======================================
  Coverage   94.00%   94.00%           
=======================================
  Files          59       59           
  Lines        4924     4924           
=======================================
  Hits         4629     4629           
  Misses        295      295           

Impacted Files	Coverage Δ
aquadoggo/src/materializer/service.rs	94.88% <ø> (ø)
aquadoggo/src/graphql/schema.rs	92.64% <100.00%> (ø)
aquadoggo/src/manager.rs	95.83% <100.00%> (ø)
aquadoggo/src/node.rs	84.61% <100.00%> (ø)

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