chore: merge duplicated changelog lines for guzzlehttp/psr7

[phil-davis]

I accidentally duplicated this in #41635

[DeepDiver1975]

🤖 Automated review by Claude Code review agent.

Overview

This is a small changelog-housekeeping PR that merges two duplicated guzzlehttp/psr7 entries in changelog/unreleased/PHPdependencies20260225onward into a single line. The duplication was introduced in #41635 (per the author's note) and was previously flagged by an automated review of #41600. The change is +1/-3 across a single file. It does exactly what it claims.

Code quality / style

• The merge is clean and correct: guzzlehttp/psr7 (2.8.0 to 2.10.4) and guzzlehttp/psr7 (2.11.0 to 2.12.0) are collapsed into guzzlehttp/psr7 (2.8.0 to 2.12.0).
• The two original ranges are contiguous (2.10.4 → 2.11.0 are successive update steps), so combining them into 2.8.0 to 2.12.0 accurately represents the full version span with no information lost.
• The merged entry remains in the correct alphabetical position within the guzzlehttp/* group, matching the file's existing ordering convention.
• Blank-line separation between entries is preserved, consistent with the rest of the fragment.

Specific suggestions

None. The change is minimal and correct as-is.

Potential issues / risks

• Verified the full file at the PR head: all other dependency entries are untouched and the trailing PR-reference block (#41450 … #41635) is unchanged. No distinct PR/issue references were lost — the references are aggregated at the bottom of the fragment rather than per-line, so the merge does not drop any.
• Only one file is changed (changelog/unreleased/PHPdependencies20260225onward); no source or unrelated changelog files are disturbed.
• This is a changelog fragment only, with no runtime impact.

Looks good — recommend merging.