[CHERRY-PICK] [SQUASH ON REBASE] Update FlattenPdbs Plugin to pick up additional symbols.

[os-d]

Description

This commit was missed bringing from 2502 to 2511. Cherry-pick it. On the next integration, it can be squashed with
7784980.

(cherry picked from commit f90aa00)

• Impacts functionality?
• Impacts security?
• Breaking change?
• Includes tests?
• Includes documentation?

How This Was Tested

N/A.

Integration Instructions

N/A.

[mu-automation]

✅ QEMU Validation Passed

Source Dependencies

Repository	Commit
mu_basecore	a36107b
mu_tiano_platforms	f61452e

Results

Platform	Target	Build	Boot	Overall Boot Time	Build Logs	Boot Logs
Q35	DEBUG	✅ success	✅ success	0m 16s	Build Logs	Boot Logs
SBSA	DEBUG	✅ success	✅ success	0m 29s	Build Logs	Boot Logs

Workflow run: https://github.com/microsoft/mu_basecore/actions/runs/24534340268

This comment was automatically generated by the Mu QEMU PR Validation workflow.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (release/202511@9658bab). Learn more about missing BASE report.

Additional details and impacted files

@@                Coverage Diff                @@
##             release/202511    #1769   +/-   ##
=================================================
  Coverage                  ?    2.21%           
=================================================
  Files                     ?     1633           
  Lines                     ?   420176           
  Branches                  ?     4949           
=================================================
  Hits                      ?     9308           
  Misses                    ?   410793           
  Partials                  ?       75           

Flag	Coverage Δ
FmpDevicePkg	9.53% <ø> (?)
MdeModulePkg	1.58% <ø> (?)
MdePkg	5.44% <ø> (?)
NetworkPkg	0.55% <ø> (?)
PolicyServicePkg	30.42% <ø> (?)
SecurityPkg	1.59% <ø> (?)
UefiCpuPkg	4.78% <ø> (?)
UnitTestFrameworkPkg	11.70% <ø> (?)

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