[Port] Changing container image from custom to standard ubuntu

[Benjin]

Since we've removed our custom infrastructure from Azure, the release branch needs to be updated.

This change was originally part of this commit, but I'm being more selective with the port to the release branch.

[coveralls]

Pull Request Test Coverage Report for Build 9554144298

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.002%) to 41.757%

---

Files with Coverage Reduction	New Missed Lines	%
extensions/notebook/src/book/bookTreeView.ts	1	36.91%
<!--	Total:	1		-->

Totals
Change from base Build 9506383047:	-0.002%
Covered Lines:	30827
Relevant Lines:	69082

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9554891788

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.003%) to 41.756%

---

Files with Coverage Reduction	New Missed Lines	%
src/sql/workbench/services/connection/browser/connectionDialogWidget.ts	1	73.44%
extensions/notebook/src/book/bookTreeView.ts	1	36.91%
<!--	Total:	2		-->

Totals
Change from base Build 9506383047:	-0.003%
Covered Lines:	30826
Relevant Lines:	69082

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9569551250

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 5 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.009%) to 41.75%

---

Files with Coverage Reduction	New Missed Lines	%
src/sql/workbench/services/connection/browser/connectionDialogWidget.ts	1	73.44%
extensions/notebook/src/book/bookTreeView.ts	1	36.91%
extensions/sql-database-projects/src/common/httpClient.ts	1	66.18%
extensions/sql-database-projects/src/dialogs/publishDatabaseDialog.ts	2	52.03%
<!--	Total:	5		-->

Totals
Change from base Build 9506383047:	-0.009%
Covered Lines:	30823
Relevant Lines:	69082

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9571119133

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.003%) to 41.756%

---

Files with Coverage Reduction	New Missed Lines	%
src/sql/workbench/services/connection/browser/connectionDialogWidget.ts	1	73.44%
extensions/notebook/src/book/bookTreeView.ts	1	36.91%
<!--	Total:	2		-->

Totals
Change from base Build 9506383047:	-0.003%
Covered Lines:	30826
Relevant Lines:	69082

---

💛 - Coveralls