[MM-63434] Use forked PDF library with parsing depth limit (cherry-pick #35947) (#36177)

* [MM-63434] Use forked PDF library with parsing depth limit (#35947)

* [MM-63434] Use forked PDF library with parsing depth limit

Replace github.com/ledongthuc/pdf with a fork that limits object
nesting depth during parsing. Add test coverage.

* Reverting incorrect merge that lost the change to msgpack

The error was in merge 64bdff88d8

* Remove stale ledongthuc/pdf checksums after fork replace (go mod tidy)

* Fix TestPdfFile expected text for forked PDF extractor (release-10.11)

The jgheithcock/pdf fork returns a leading newline for sample-doc.pdf; align
with master and 11.x cherry-picks.

server/go.mod

@@ -248,10 +248,6 @@ exclude (
 	github.com/willf/bitset v1.2.0
 )
 
-// Prevent from being upgraded because this library has a minimum requirement
-// of Go 1.24.
-replace github.com/ledongthuc/pdf => github.com/ledongthuc/pdf v0.0.0-20240201131950-da5b75280b06
-
 // Also prevent tablewriter from being upgraded because the downstream dependency
 // jaytaylor/html2text does not have a go.mod file which makes it bump to the latest
 // version always. Tablewriter has made breaking changes to its latest release.
@@ -259,3 +255,6 @@ replace github.com/olekukonko/tablewriter => github.com/olekukonko/tablewriter v
 
 // See MM-66167, MM-68222 for more details.
 replace github.com/vmihailenco/msgpack/v5 => github.com/mattermost/msgpack/v5 v5.0.0-20260408165622-cadfad56a815
+
+// See MM-63434 for more details.
+replace github.com/ledongthuc/pdf => github.com/jgheithcock/pdf v0.0.0-20260404175814-28cd6530c1fe