add missing strip_prefix

[Thanhphan1147]

The code to strip the ingress prefix was present when synapse was using ingress v1 but was missed when moving to the v2 lib. So this PR adds it. synapse can't handle prefix so this is needed to function properly.

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Manging Charm Complexity
• The documentation is generated using src-docs
• The documentation for charmhub is updated.
• The PR is tagged with appropriate label (urgent, trivial, complex)

[github-actions]

Test coverage for 69f73eb

Name                                    Stmts   Miss Branch BrPart  Cover   Missing
-----------------------------------------------------------------------------------
src/actions/__init__.py                     1      0      0      0   100%
src/actions/register_user.py               21      0      2      0   100%
src/admin_access_token.py                   9      0      0      0   100%
src/backup.py                             175      5     20      2    96%   353-354, 423-424, 480->482, 483
src/backup_observer.py                    134     16     12      0    89%   132-135, 140-143, 179-182, 211-214
src/charm.py                              288     20     70     11    91%   136->138, 141, 247, 251-252, 258-259, 280-281, 309, 316, 397-401, 404-405, 433-435, 455, 491-492
src/charm_state.py                        151      8     30      6    92%   271, 275, 296, 321, 327, 333, 337-338
src/charm_types.py                         34      0      0      0   100%
src/database_client.py                     57      1      8      4    92%   35, 47->exit, 69->exit, 88->98
src/database_observer.py                   39      0      4      1    98%   70->72
src/exceptions.py                           3      0      0      0   100%
src/matrix_auth_observer.py                60      5     12      3    89%   61, 64, 148, 167-168
src/media_observer.py                      41      4      2      1    88%   61-63, 82
src/mjolnir.py                             97      3     30      3    95%   82, 91->107, 112-116
src/observability.py                       14      0      0      0   100%
src/pebble.py                             205     27     48     13    84%   57->62, 176->exit, 187-191, 225-226, 246-247, 300->305, 308-309, 321-322, 324-325, 343-344, 361, 363, 365, 367, 369, 397, 449-454
src/redis_observer.py                      35      3      4      0    92%   62-65
src/s3_parameters.py                       22      0      4      0   100%
src/saml_observer.py                       31      0      4      0   100%
src/smtp_observer.py                       56      4     14      2    91%   82-86, 89, 108->113
src/synapse/__init__.py                     4      0      0      0   100%
src/synapse/admin.py                       19      2      2      0    90%   40-41
src/synapse/api.py                        175      3     20      3    97%   176, 229, 402
src/synapse/workload.py                   139      6     24      0    94%   405-406, 416-419
src/synapse/workload_configuration.py     170     29     40     14    80%   85->exit, 89-90, 138-139, 168, 188-189, 221-222, 255, 264-265, 280, 285-286, 307-308, 327->332, 333, 351->353, 363-364, 380, 427->430, 454-455, 483, 491->493, 493->495, 500-501, 521->528, 531, 551-552
src/user.py                                23      0      2      0   100%
-----------------------------------------------------------------------------------
TOTAL                                    2003    136    352     63    91%

Static code analysis report

Working... ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100% 0:00:00
Run started:2024-11-07 15:19:36.044323

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 11243
  Total lines skipped (#nosec): 4
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):