Add default namespaces to relevant Grand Bend Sample data

Summary of outcomes for Data Standard 2.1

• Problem Addressed: Sample xml files do not consistently include a default namespace for Assessments, LearningObjectives, and LearningStandards.
• High-level Reasoning: The Ed-Fi ODS uses vendor namespace to version authorization of some entities. The sample xml will be more helpful if a default namespace of "http://ed-fi.org" is included as a placeholder for Assessments, LearningObjectives, and LearningStandards.
• Changes Made: Added namespace value of "http://ed-fi.org" to Assessments that did not previously have a namespace included; Corrected values of "http://www.ed-fi.org" to "http://ed-fi.org" for LearningObjectives and LearningStandards that had listed the incorrect namespace

Original ticket description follows:

The Ed-Fi ODS uses vendor namespace to version authorization of some entities, and the Ed-Fi sample XML will be more useful if these entities carried a default namespace of "http://ed-fi.org": Assessment, LearningObjective, and LearningStandard

See ODS-680 for more details