fix: Expose VaultedPaymentMethod initialiser

[NQuinn27]

Description

CHKT-XXXX

• Makes initialiser for VaultedPaymentMethod public.
• Adds convenience initialiser for CardNetworkAsset from network string

Contributor Checklist

• All status checks have passed prior to code review
• I have added unit tests to a reasonable level of coverage where suitable
• I have added UI tests to new user flows, if applicable
• I have manually tested newly added UX
• I have open a documentation PR, if applicable

Reviewer Checklist

• I have verified that a suitable set of automated tests has been added
• I have verified that the title prefix aligns to the code changes + whether a release is expected after merging the PR
• I have verified the documentation PR aligns with this PR, if applicable

Before Merging

• If introducing a breaking change, I have communicated it internally
• Any related documentation PRs are ready to merge

Other Stuff

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[github-actions]

	Warnings
⚠️	Please assign someone aside from CODEOWNERS (@checkout-pci-reviewers) to review this PR.

Generated by 🚫 Danger Swift against b548715

[github-actions]

Appetize link: https://appetize.io/app/hrn4irt43mht3e2gmzjv7zj7kq

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
80.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud