chore: Remove redundant LICENSE files from individual crates

[cijothomas]

Remove individual LICENSE files from all crates since they are redundant with the license = "Apache-2.0" field in each Cargo.toml.

• Removed LICENSE files from 12 individual crates
• Kept root LICENSE file and proto LICENSE file (from upstream)
• All crates retain license = "Apache-2.0" in their Cargo.toml

The license field in Cargo.toml is the recommended approach for well-known licenses like Apache-2.0, and Cargo will properly handle license information when publishing to crates.io.
https://doc.rust-lang.org/cargo/reference/manifest.html#the-license-and-license-file-fields

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.1%. Comparing base (e9ca158) to head (9edc74d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #3086   +/-   ##
=====================================
  Coverage   80.1%   80.1%           
=====================================
  Files        126     126           
  Lines      21957   21957           
=====================================
+ Hits       17603   17604    +1     
+ Misses      4354    4353    -1     

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[Copilot]

Pull Request Overview

This PR cleans up the license structure by removing redundant LICENSE files from individual crates while retaining license metadata in Cargo.toml files.

• Removed 12 individual LICENSE files from various OpenTelemetry crates
• Maintained license information through license = "Apache-2.0" field in Cargo.toml
• Streamlined license management to use Cargo's recommended approach for well-known licenses

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
opentelemetry/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-zipkin/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-stdout/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-semantic-conventions/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-sdk/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-proto/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-prometheus/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-otlp/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-jaeger-propagator/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-http/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-appender-tracing/LICENSE	Removed redundant Apache-2.0 license file
opentelemetry-appender-log/LICENSE	Removed redundant Apache-2.0 license file