Bump httpclient allowed payload limit

[qwertyuu]

Goal

Bring the upload limit closer to the actual Bugsnag's error reporting limit, see: https://github.com/bugsnag/bugsnag-dotnet/blob/96360fb0f8d31f5fd6a8f3f17184bd626421820e/src/Bugsnag/Payload/Report.cs#L16

from bugsnag-dotnet. Also here in the documentation: https://docs.bugsnag.com/platforms/dotnet/asp-net/configuration-options/#maximum-breadcrumbs

Changeset

Changed

Changed MAX_SIZE const in HttpClient to 1024*1024, or 1048576.

Tests

Used the new constant to ensure that "massive payloads" are properly tested if the value ever changes.

Review

For the submitter, initial self-review:

• Commented on code changes inline explain the reasoning behind the approach
• Reviewed the test cases added for completeness and possible points for discussion
• A changelog entry was added for the goal of this pull request
• Check the scope of the changeset - is everything in the diff required for the pull request?
• This pull request is ready for:
  • Initial review of the intended approach, not yet feature complete
  • Structural review of the classes, functions, and properties modified
  • Final review

For the pull request reviewer(s), this changeset has been reviewed for:

• Consistency across platforms for structures or concepts added or modified
• Consistency between the changeset and the goal stated above
• Internal consistency with the rest of the library - is there any overlap between existing interfaces and any which have been added?
• Usage friction - is the proposed change in usage cumbersome or complicated?
• Performance and complexity - are there any cases of unexpected O(n^3) when iterating, recursing, flat mapping, etc?
• Concurrency concerns - if components are accessed asynchronously, what issues will arise
• Thoroughness of added tests and any missing edge cases
• Idiomatic use of the language

[GrahamCampbell]

@kattrali I wonder if the payload limit was 512kb in 2015, which would explain why the code is like this?

[kattrali]

Thanks @qwertyuu! I took a quick look and it seems fine aside from a few small issues.

[qwertyuu]

@kattrali 👍

[qwertyuu]

@kattrali Comment added!

[kattrali]

Thanks for the quick edits! ⚡️