[Rust-Axum] Support quotes in string literals

[Victoria-Casasampere-BeeTheData]

Allows quotes to be used in string default values. Currently, using default: "test \"foo\" bar" leads to code that fails to compile. This patch puts all string literals in r#""#, solving the issue.

Depends on:

• [Rust-Axum] Dynamically set the types of integer literals #20133
• [Rust-Axum] Fix: handling non-lowercase Header in Request/Response #20178

Samples will be updated when they merge, but they should not have any merge conflicts.

# Command used to update the samples
mvn clean &&
./bin/generate-samples.sh bin/configs/manual/rust-axum-* &&
mvn integration-test -f samples/server/petstore/rust-axum/pom.xml

@linxGnu @wing328

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[linxGnu]

LGTM. Please update the sample and integration tests after #20178 and #20133

[Victoria-Casasampere-BeeTheData]

Ready for merging @wing328

[linxGnu]

LGTM. Thank you for great contribution @Victoria-Casasampere-BeeTheData