Add better provider parsing errors messages

[foosiee]

Description of changes

Added cause of error to Entity and Policy provider parsing errors

Issue #, if available

#67

Checklist for requesting a review

The change in this PR is (choose one, and delete the other options):

• A backwards-compatible change requiring a minor version bump to cedar-local-agent (e.g., addition of a new API).

I confirm that this PR (choose one, and delete the other options):

• Updates the "Unreleased" section of the CHANGELOG with a description of my change (required for major/minor
  version bumps).

Testing

Ran local build

Error difference

// before
EntitiesError("/var/folders/_g/9l0dzppx423c5j0x0b9z_qgm0000gs/T/.tmpXeRe8r")

// after
EntitiesError("/var/folders/_g/9l0dzppx423c5j0x0b9z_qgm0000gs/T/.tmpXeRe8r", Deserialization(Serde(Error("invalid type: map, expected a sequence", line: 1, column: 1)

[github-actions]

Coverage after merging provider_error into main

86.86%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
src/public
simple.rs	34.72%	100%	36.78%	26.19%	101, 103–107, 126, 146, 148, 151–158, 165–178
mod.rs	5.26%	100%	5.26%	100%
src/public/events
receive.rs	55.10%	100%	51.28%	70%	28–29, 36
core.rs	50.98%	100%	41.38%	63.64%	133, 138, 156–159, 163–165, 170, 54–55, 77–80
src/public/file
policy_set_provider.rs	72.85%	100%	60.61%	96.15%	143, 175
entity_provider.rs	72.27%	100%	59.59%	92.39%	182, 189, 194, 228, 247–249
src/public/log
schema.rs	41.19%	100%	24.52%	95.83%	173, 349–352, 509, 880, 898–899, 911
error.rs	76.09%	100%	60.71%	100%
mod.rs	59.81%	100%	57%	100%
event.rs	83.33%	100%	68.18%	100%

[mtrottie]

LGTM