Fix a bunch of places we forget to aws_raise_error()

[graebm]

See: awslabs/aws-c-common#1089

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (8e5e461) 79.67% compared to head (a3d7b54) 79.57%.

Files	Patch %	Lines
source/signable_chunk.c	0.00%	2 Missing ⚠️
source/signable_http_request.c	0.00%	2 Missing ⚠️
source/signable_trailer.c	0.00%	2 Missing ⚠️
source/aws_imds_client.c	0.00%	1 Missing ⚠️
source/aws_signing.c	0.00%	1 Missing ⚠️
source/sigv4_http_request.c	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #229      +/-   ##
==========================================
- Coverage   79.67%   79.57%   -0.10%     
==========================================
  Files          33       33              
  Lines        5834     5841       +7     
==========================================
  Hits         4648     4648              
- Misses       1186     1193       +7     

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